Refurbishing and simple modification AKG K340 ES-D

Old headphones AKG K340 with dynamic and electret driver inside of each cup (and some speaker crossover) refurbishing and simple modification:
1)Many users / reviewers are presenting modification of internal grill to leave more space for air (removing grill completely or cuting huge holes or printing 3D replacement). I have decided to make a smaller modification in the same direction - drill out square holes 1.5x1.5mm to diameter 2.1-2.2mm. Drilling was costless. I am not able to provide measurements but difference is a little bit noticeable only.
2) Elastic straps visually were still OK but quite heavy headphone was not fix on my not the smallest head. That is why straps have been replaced with thicker (diameter 1mm) and shorter ones.
3) Headband visually was still OK but I have replaced with leather one.
4) Ear pads according to all sources that I have checked, should be the same as for other K2 series (like K240 K260). It unexpected that I was not able to fit on those headphones ear pad replacement dedicated for K2 series. Even more, old ear pads put back to the headphones also is very difficult. I have installed new ear pads from Superlux HD681B - those having the same size but larger elastic rubber lip around what lets to fit earpad easier.
5) Outside of each cup is placed screw with visual marks of wearing. I have seen that sb else cover those screws by rubber sticker, so did the same.