I do believe you can use sandpaper to sand it down, problem is that aftewards the spot that was sanded will look bad (and possibly feel rough) but the other question is, is it hollow inside? If so, how thick are the walls? If they are thin and you sand it down, at worst it can just open a hole or at least make it more fragile.
@pylaczynski knows more about this than I do so maybe he has some better idea…
I would believe that the shell-chamber is indeed a different printed target.
One does not change size+curvature to adapt to community request and tell (me/us) its randomly hand made.
The chamber the speakers sit, has to follow depth targets as that influences’ air pressure targets (as also the airduct)
But it is a bit bizarre that they are supposed to sound the same. Can not verify sadly. Can not measure them.
The faceplate protective layer is thicker and irregular, which makes them standout outside of the ear.
This causes pressure on the bottom part, stretches the ear downwards and shrinks it a bit.
Soo the 200µm slightly bigger shell that should be barely an issue, becomes an issue.
The rermain part that bothers, outside of one being deeper it than the other ~ is the shell curvature
Its too sharp and reminds me of the Tangzu Xuan Nv ~ which was going for the same sharp shape.
It may work out if the shell is not as wide, but its too sharp even if rounded.
They went back on the 3rd day but gladly amazon and other e-tailer have no issue with a return.
Common selling practices for buying products online.
The right shell actually does fit fine
~ aka what everyone hopefully got here, but the left is soo different in everything.
If it was mirrored and both were bad, at least it was sellable them. But this, what is this failure 
I believe it should be in the realm of possibility, but that’s another ~60$ for products.
Clear (medical grade) resin, 2000+ grit sanding paper & reading a bit there are some 12-15K grit glas? hand-files for resin work.
Issue being exaugurated due to stretching by no size control when swapping batches,
and generally big coating targets.
Else idea of sharper spike can work, if you don’t mess up everything else too.
Sanding the top (inside) layer will be an issue & indeed may reach chamber, but sanding outside is required too.
This combined batch product should not exist. 3 mistakes in one product.
But key-mistake is combining unfitting batches.
.
The best outcome would still be for Meyer-Audio to stand by their mistake and replace them.
Give an updated matched set,
Stop offloading your inventory onto customer when they pay for a premium product
Actually tighten down QC so such big margins do not happen, neither accept different size shells as one product.
And stop lying about manufacturing to dodge warranty & cause your e-tailer partners trouble.
When the real person that messed up is Meyer-Audio’s team;
Although e-tailer equally doing excuse switching due to B2B relationship & wants to keep near 50% of the item cost as a gift. No comment;
E-Tailer trouble for another day, but it is Meyer Audio that doesn’t stand to their products.
It was soo easy to just resolve it and forget, because you had a good product release streak.
, but has to eat the blame now tooSadly the company & consumer support especially ~ failed.
QC failed too , but humans make mistakes.
They are soo competitive and i really want to keep them or even upgrade to 400$ version,
but this treatment is not ok~! 
This is totally BS, even if the ONLY change is a thicker wall on one compared to the other, that WILL have an effect on the sound, the question is if it is actually audible or not to our human ears though.
My issue is, i dont know.
Because it can’t be perfectly insert. I can not afford proper measuring gear.
One knows if you pull up the ear top ~ it changes ear canal
If you press your ear top to the head, sometimes it amplifies bass
(different humans different sticking ears, haha)
Like i understand if one pair is bad production and you want to meet tight audio-qc , you may redo or reuse
But at least get them right size …
Maybe pressuring both e-tailer + Meyer Audio by bad measuring data.
Who knows if they are 85% or 98% fine
But you still can deny with “it does play, right” comment.
Ahhh such a trouble. I really tried the politeness private path for soo long …
I just wish to enjoy the product, because the team that tunes them does such a good job.
The resin artist is very talented too. 
But you call it mark two, and had PA02 & CKLVX products. Many many user with many reports
You had SL41 first gen too, to “learn” how to make a shell and learned.
Changed shell size mid product. I’m aware.
Why is this issue even a thing.
Why do i have to be publicly annoying~~
It has an effect since the size is different which leads to a different mass which will then affect the resonance.
Damn! Looks like two different models…
Insane that they won’t replace them.
I have never sanded bought IEM (or anything printed to such large extent honestly as it is always easy to reprint) as it is mostly unclear what is the shell thickness, but reworking acrylic resin is in general quite time consuming, not very easy process and it is always compromising for things you mentioned.
It is definitely doable though with enough patience, sandpaper (grits from 320 up to 1200 or even 1600/2000 if you are very stubborn), water (very recommended due to cleanliness and health and safety reasons) and finished with acrylic clear coats to make it smooth for ear contact 
I have seen some people removing similar “wings” from Blessing 2 though with quite success from functional perspective at cost of not very aesthetic look.
Any support and push is strongly appreciated.
Once again sorry that i have to enter this community with such bitter taste 
~ but i need some advice from people who understand much more than me 
Stubborn indeed, because its not a 20$ product mistake.
Other option is deal with e-tailer, gift half the pricetag and swap both IEM Vendor & E-Tailer.
Both are bad options, but the most logical.
Well real options are:
~ Sell them locally to some poor soul as they recommend, where no human will have a good time with those
~ Fix it, show how a proper job is done & hope at least that me as victim will improve future company products.
Although last one is an open question if i would buy again from them.
Sadly that OEM supplies more IEM-Vendors with products. The issue isnt soo small;
If they were a sub-optimal ChiFi (annoying word) product, i would not bother
But the engineers are talented, the artwork person is too. Its soo uselessly unfortunate.
About E-Tailer,
i have some unfortunate communication with them ~ but i just wish for a resolve and to move on.
Not stain my name with bad PR. Especially with similar workplace/workfields
Thank you for the inspiration.
If you find time and remember where those posts were, please PM me them~
If company or rep won’t contact me here or on e-mail (got my data and serial number is visible)
I’ll consider what to do with e-tailer and then keep you up to date with the work procedure 
Maybe somebody will buy them away, but i don’t feel to good putting MeyerAudio’s mistake onto another soul. It will not fix anything but i just get “richer” , well compensate losses.
Also will feel me with shame wearing their logo, when i have to “redesign” the shell.
This is a pic from a fellow polish forum member Moondrop - fanklub - strona 5 - Słuchawki ogólnie - forum.mp3store.pl
This is another mod of the nozzle of the blessing, but similar case nonetheless: Moondrop problems | Audio Science Review (ASR) Forum
