Alright, so I took apart a go-cart after coming home, cleaned it, and used a length of PTB twice as long as the cotton inner wrap since the new material was so much thinner. I wrapped the new ptb inner wrap around a coffee stirrer, then wrapped that with the poly-fill. After re-inserting around the tube in the go-cart, it looked something like this:
Just like a new one from the post office. It works just the same, too, after loading with juice. So far, no down-side to re-loading them with this mod. Unfortunately, no real gain, either. I may try another one with a piece of PTB that is the same length as the original inner wrap and see what that does for wicking. If the PTB proves to be "burn-proof" around the coil, I would call this a solid design change.