I would probably agree with
@2aBaCa if I had ever bought a premium matched receiver set.
I'm sure for the money I would really be pissed if they didn't fit perfect.
Can you buy a 3 or 4 piece matched set? 3 uppers all matched to one lower?
Or are you stuck with a matched set for every purpose?
Maybe a .223, a .224V, and 22 Grendel upper?
You could always ream the holes to match an oversize pin and get at least a good one point fore and aft fit relying on the upper to hold everything together nice and tight. Maybe save that to correct wear.
Bedding does sound like an option but making it pretty around the edges where it might be seen takes skill
The soft approach with the wedge feels tight but is it really? When things go bang does the wedge give?
Does it give with a heavier F-Class gun?
I have a couple uppers that I like to fit to one lower, all set up for prone 600/1000.
I can fit each upper to that lower. They also fit some of the others but not all.
Each has it's own scope.
If it wasn't for the AR-Lego aspect, I'd probably be more into bolt guns.