Mylar vs Kapton Tape belt drive

There is very little info on the differences. One post said the kapton was too slippery. Can anyone else confirm this?.

Both these products have about the same tensile strength, with the slight nod going to Kapton. My question pertains to Ultimate Elongation. The Kapton can elongate up to 25%, vs 10% for Mylar.

Part of me thinks kapton would be better. You could start the material (belt) a little on the tight side, and it would settle in. I do have variable speed on my TT.

Part of me thinks it would be worse. Are we not trying to eliminate 'any' expansion in the 'belt' whatsoever?.

If I have to get a capstan manufactured, would I be better to use a 1" tape drive?. BPB Inc makes seamless belts.

If most machined metals tend to be smooth, should I get a capstan made out of hardwood?.

Any thoughts?.

Cost for me is not an issue.