I managed to do a few different vinyls on the one belt. Not sure what it was made of but i suspect nylon as the ends are heat cut.
They seem to bond quite well although the belt was a particularly heavy texture. The texture shows through on all but the red sparkle. I have pulled, twisted and rolled the belts with no visable difference to the vinyls.
Vinyl used was red sparkle, gold foil, black flex, red flex, white flex and a hot fix star. The pressure was too much for the star though and it was squashed into the material with the glue coming out around the side. Less pressure and heat would be better.
The last photo are samples i recieved, some are denim effect and some are carbon effect and because these are already heavy textures i would imagine they will go on better.
Hope this helps.