Lots of experience listed above.
As for me.
Currently I still have a 25 pound restriction. It's better than the 5 pound and 15 pound ones I had earlier. Most of my long gun stuff has been slow fire off of 'rice bags' (like a sand bag only filled with rice, much lighter and I can carry them out to the pick nick table).
Before my surgeries I preferred to stand. As this was only target work, it is acceptable.
I never like the concept of 'prone' or 'off of a barricade'. Where I retired from was most all concrete and at the previous employment I had experimented with 'skip shot', mostly pistol and shotgun. Nope, I don't think I want to get into the line of 'skip fire'.
Younger, I was always too squishy and a setting position was more of a on my butt wiggle position. (set on the floor, place the bottoms of both feet flat together, rest both knees on the floor - squishy - no solid support.)
Another thought, mobility. Flat on the ground or flat on your butt, move fast.
It goes back to basic training; breathing, sight picture, trigger squeeze. Stable positions are a continuation. Weaver or isosceles, 'push-pull' or 'cup & saucier', sitting/prone/standing. If 'it' is a 'game' or for competition, set the position. To live in an actual gun fight, forget it, I will do what I know works. I know, 36 years of staying alive or preparing has me in a mind set to innovate, change tactics often, move and live.
I am amused when I think of shooting the old 'PPC' course. Amble back to the 50 yard line and take up position by a wobbling 4 by 4 stuck into a pipe in the ground. Slow fire, single action, with a 4 inch .38 Special using the cheapest 148 grain grease ball wad cutters. Oh yes, that was useful, not.
Time is close for me to go to the pharmacy for more meds.
Thanks for a hobble down memory lane. Wonder what my BP is now?