I take a different view point. If you're reloading at 7500psi which many of us do for the older guns, then a 1000psi or so isn't going to mean very much. A couple of years back I called Clay Busters and ask if it was ok to sub in different wads [ for short shells ]. I had told him I was loading around 7500psi. He said he couldn't answer officially without testing, BUT he wouldn't be afraid to sub in a different wad if it was from the same manufacture with the same over powder base. All you're changing is the length of the cushion part. The part where the powder sits, it's length or diameter, hasn't changed one bit so why would pressure change ? If you're going to insist it does, is it enough to make a difference ? I've reloaded for shotguns since 1970 and shot and reloaded for Damascus barreled shotguns since 2005. In all those years of shooting 2 3/4, or 2 1/2 or even shorter shells like 2" I have never sent a shell in for testing. Sometimes I go to a roll crimp [ or a Hartin crimp at times ] and don't give it a second thought. Yes, too deep a crimp of any kind will increase pressures. That's easy enough - don't crimp too deep. My 10ga guns are all 2 7/8 and there is no data for them. It's simple enough. Use 12ga low pressure data with a 10ga wad. The bigger chamber [ larger diameter ] will produce less pressure. Just use a little common sense and you'll be ok.
We're just shooting shotguns at the lower end of the pressure curve. You want pressures, shot rifle or pistol.