Nice setup.
I’m getting ready to buy/build similar, mostly for a truck/range gun.
For those that have both, pros/cons of .300 vs 5.56?
Non-suppressed, ammo availability and cost is non issue.
I've got 10.5" uppers in 5.56, 300BO, and 7.62x39. Here's how they stack up in my experience. These are generalizations, nothing is engraved in stone.
Ammo availability/cost - Advantage 5.56. (However, during one of the shortages, there was still plenty of 7.62x39 at a fair price, and that's when I got into that chambering)
Trajectory/effective range - Advantage 5.56 (if you like to stretch them out past 100 yards or so)
Muzzle blast - Advantage 300BO
Versatility for sub/super - Advantage 300BO
Lethality - either one, choose ammo according to desired effect.
Suppressability - Advantage 300BO