Update on the HE400se headband hot spot issue, velcro ties and the Sennheiser HD650 replacement padding worked the magic. The padding is just about the right length as well, no need to cut or trim anything.
You just need to move the adjustment two clicks down on each side to compensate the thickness of the padding. Looks a bit ridiculous when wearing it, but indoor use anyways, comfort comes first! Looks like Mother Miranda from Resident Evil Village when wearing it lol:
