jd140400,
I sure would be interested in the type of pastic that was used on this transformation on the old saggy bags. I also have the heritage and also the saggy bags. Is the a pastic at is from the Home depot of from your local hobby store? Oh, and did you do an insert on the lid of the bags aswhile? And the epoxy used was leather friendly I hope.
To stiffen bags, I have used the nylon plastic full sheet inserts used in old 3 ring binders to stiffen my nylon tailpack (or you could use the covers themselves). I suppose if there is a sewing machine available, you could "pillow case" them if you or someone you know is handy...