RE: Vacum forming questions
Unless you plan on doing this commercially, you are spending a lot of money for a few parts.
I use a shop-vac connected to an 8"x12" box and I heat my plastic on a frame suspended over 2 hotplates. Total cost was about $25 (mostly for the hotplates).
I can pull a 5" x 8" x 3" high windshield from .040 PETG with no problems on this setup. (The hardest part was making the plug for the windshield)
It isn't fancy, but for the 10 or 12 parts a year I need it does the job.