They served as a jumping-off point for me, and as my previous two pits had very little woodworking in them, I figured this was a good place to start learning about the process.
Just as I thought... and I'm not blaming you. However, you had a look at my cockpit, yes? Would you believe that I got maybe about 95% of the cutting done for me at the shop where I got the wood? They charged me £4 for all the cuts, sure, but all I was left to do was cut the support blocks (I do MDF-to-block-to-MDF connections, I don't screw MDF-to-MDF if I can help it) and a few angle cuts for the left and right aux panel and aux panel supports. You did more cutting with the ABC's slots than I did with my pit!
Regarding cushions, what I read was any old yoga mat, so maybe you can score one from a friend who is "upgrading" or maybe try eBay to get it cheaper? Like I said, a couple of layes (one guy said three), wrap them in cloth, and give it a try. The idea here is to find a material that does not "bottom out," but as you have discovered it is difficult to find one. You either end up with a thin layer of padding that eventually gives way or a thicker layer of padding that unfortunately pushes you too far up-and-forward. Hence my resort to a car seat. However, a car seat is wider than an ACES seat by at least a few inches, a bucket seat is even slightly wider, so you will have to make allowances for this if you decide to go this route.
As for panels, well, I've not delved into that myself as well, that is all black magic voodoo to me
But I plan on building the F-16's left aux panel soon, as soon as funds free up. From what I've read though, different controllers interface with the PC differently, and sometimes interface with the sim itself differently as well --- I've had numerous warnings of making sure XXXX controller board works with YYYY simulation before buying it.
Hope that helps, and looking forward to see what you do with your pit build!