So I have a Case sv340 skid steer and the front door got hit by a hidden piece of rebar. Shattered the glass door and slightly bent the frame work. After checking my options, Case wanted $4000.00 + for a demo door unit or $400 or so for a new piece of glass. I went after market and ordered a 1/2" thick custom lexan door glass replacement for $800.00. I spent several hours cleaning off gasket and broken glass. I then installed it in my existing metal frame using the 3m product. After a few weeks of shaking around the lexan pulled loose from the frame work and I decided I would drill some holes in it and hold it to the frame with 20 1/4 bolts 3 hours later i had it drilled and everything nice and tight and left at dark. Next day had a 100* day, while i was away at work. The lexan swelled and broke at almost every hole. I did not have any rubber washers installed and in my mind I thought having it nice and tight was the way to go. Leaving it a little loose would have given it room to move. Let my mistake help you in your foresty door installation.
All the forestry doors I've been involved with had a metal frame that went under were the nuts are in your photo. I used to buy a flat polycarbonate from a marine supplier for about $100 then cut and drill it to size.
I replaced my glass door with .5" Lexan. I got the Lexan from Racing Shield. They are one of the suppliers for CNH (found them at Conexpo one year). They make lexan for many makes however. I just used that black sealant the CASE uses and I didn't bolt the lexan in like that and I haven't had any issues. CASE does bolt it in like that on their OEM Lexan door.
I am using 1/2" lexan on my excavator for mulching and have bolted it in place. drilled the holes oversize and inserted short pieces of rubber hose, also placed pieces of intertube between the lexan and the washers. never have lost any due to fracturing.