Upholstery and Interior Questions

[5Tractorguy]

Hey guys, I'm planning on doing an extensive mechanical revamp once spring gets here on my '61 GMC and was hoping some of you can help with a few questions I have...

First, for those that have rebuilt the standard bench seats (ones with the thin foam)...

- What thickness/density foam did you use? I read the back takes 1" and the seat portion 2"... I'd really like to firm up the seat and wasn't sure if I could add an extra 1/2" to 1". Thinking of ordering everything off this site... http://www.diyupholsterysupply.com/

- Or did anyone buy the kit from Classic Industries? (https://www.classicindustries.com/pr...s/ak50104.html) And if so, how was the quality?

- Anyone use this cover from LMC? If so, decent fit? This is a work truck so it doesn't have to be perfect... https://www.lmctruck.com/interior/se...upholstery-kit


And lastly, do the arm rests all use the same bolt pattern? I'd like to buy the 64-66 rests because they are significantly cheaper than the 60-63 rests. Read the 66 and up rests are the only ones that are different but wanted to confirm first.
64-66 rests on Ebay