My 1981 GTC has a custom top made of Stayfast canvas on it, and it works pretty well.
There are a number of shops that specialize in custom tops, and maybe we could get 4 or 5 guys together and and order up several tops. It will certainly drop the price, and once a template is done, it's a lot less expensive.
Here's the message I got from Purring Pumas when I asked them about the quality of the conv top. (As usual, they were very professional)
I am sorry to hear that you were disappointed with the quality of the Puma top you purchased recently. We understand that it is not of a material equivalent to that of BMW’s or similar cars in the USA. Such materials are simply not available in Brazil. We have searched a lot throughout Brazil for convertible tops for Pumas and this is the best quality top we believe is made in Brazil. As one of its features, It has heat-sealed seams to minimize water leakage, which others don’t. As far as the fit, the installation takes quite a bit of fitting as the frames are not all exactly the same. We are continuing to search for higher quality parts in Brazil during every trip we take down there. We only purchase the finest quality parts we can find. We have changed suppliers for certain items once we locate a better quality product.
We will continue to strive to always improve the quality of the parts we carry, but we hope you understand that we are limited by what is available.