Update: finding a seat that was both comfy and not exposed to the elements was harder than I thought it would be, but I eventually found a 5-Series seat that worked and that I thought I could get out. Pro tip: bring some small gauge wire with you to use with the batteries they will have on site to move the seat forward to get at the back seat rail bolts. I ended up brute forcing it off the seat rails itself, and I was barely able to do that with the hand tools I brought.
All in all the end result is pretty satisfactory, I don’t have as much adjustment as I would if I had been able to get the rails out, but as I didn’t plan to attach it to my wheel frame (my frame is collapsible for easier storage) it’s not a big deal. I was able to adjust the back angle by jumpering the power to my car battery, so it fits well now and is much more solid and comfortable than the old desk chair I was using. As a bonus I top mounted my pedals the night before, as I was sick of having them moving around, and also my FiST has top mounted pedals so it feels more natural to have the top pivot.
I think I’m going to swing by a pick and pull after work today and look for a seat for my sim rig, any particular models I should be looking for? I’m fairly slim and tall (6'4", 210). I’m thinking a WRX or something similar, but really as long as it’s a manual track I don’t care too much...