I got the results from two loads I sent to the proof house, both are milder than I expected, I thought they would be close to maximum.

I'm especially interested in the load with S062 which does 736 m/s / 2410 fps with about 3300 bar / 48k PSI. Shot it through my BRNO, mild recoil, burns super clean.
Carefully bumped the load up from the measured 68.5 to 72.5 grains. Recoil was noticeably increased but the primer did not flatten or crater, bolt lift + extraction was super easy and the case did hardly grow at all.
Unfortunately my crony did not give me a reading testing the loads, it does well with everything up to .308 but for some reason it fails to measure the .375. But if I had to do a rough estimate I'd say it should be around 760-770 m/s / 2500-2530 fps or so.

I'll have to wait till the whole corona situation has cleared up a little to do serious shooting and testing though. Its really bad here right now.

I cannot mention enough how much I love this rifle and cartridge. Recoil is big yet slow, the rifle just rises and pushes me back, its not really a kick. I once had a 7.5lbs 45-70 1886 with a steel butt plate and a short stock and loaded with 300 grain bullets to about 2100 fp/s this thing felt like getting hit with a baseball bat. 10 shots was enough to make me flinch.

Right now I'm tempted to scope it, I have a 2-7x33 Zeiss scope laying around, but it does have really nice express sights. In my head scoping it would kind of ruin its dangerous-game hunting flair, yet with the scope it would be a much more useful rifle. Decisions, decisions....