This is quite the build! Beautiful truck in progress. I'm also envious of you getting to work on it with your dad and spend your Saturdays together at the shop. Not as envious of the Ford clowns, haha, but actually that's pretty cool. I just ran across this USA manufacturer in another thread. They don't sell direct, but jegs seems to have decent prices on them. Saved to my info list and thought I would drop it here for your firewall insulation.
Firewall pad, door window seals:
http://www.repops.com/product-search...=2&mo=102&yr=1