Right now I'm long on want and short on time. I've been able to load 11 fireforming rounds. The first of them were Trail Boss and the next 6 were the lowest max charge of IMR3031 I could find. 3031 scares me a bit, since I'm loading with no real data and it proved hotter than QuickLoad expected in 7mm-08.
Hot is good, at least for fire-forming.
If all else fails, just start low and work up with standard .243 data.
Did you headspace for the classic "crush fit" on standard cases?
Or just set the barrel where you wanted it for .243 AI only?