I'd look to the Barnes 85 grain TSX bullet, there may be more right around that weight. For the powder somewhere in the 4350 range, looking at official data of course.
Just a reminder, don't take data for regular 85 grain 'cup & core' bullets, the all copper has a good chance of a lower max.
I have 50's & 45 Cal M-L's. Nothing against the 52, but components are much more plentiful with the 50, then the 45 isn't to bad.
If I had a 52 cal Knight I'd be happy with it, just have to plan ahead with supplies.
One has to check Regs carefully in the State they plan to hunt. The particulars can vary a good amount. I usual hunt WI, MI or IL with a M-L, each allow most anything now.
I use a Knight with a Zeiss 3-9 Conquest usually, B209 powder of course. I go back & forth between the 50 and 45 cal...