Long Range Canuck
With OAL I'm guessing it will be limited by the magazine size before you hit your chamber limit and then adjusting your powder load to tailor for accuracy. I haven't reloaded for my XCR yet but when I do I will probably stick to similar loadings and seating depths as Hornady Factory Amax loads or a higher end factory loading to avoid any potential problems, I know the semi can not take anywhere near the loads my custom bolt guns can. Personally I would play it on the safe side and stick to high performing factory loadings I don't think you can tweak more than 1MOA out of the XCR as a whole, but you might if you were lucky enough to get a real tight rifle, In this case I would pick a Safe load and then get to know what that load will do at all effective ranges...know your dope for the load and gain accuracy through consistency in all else.
Just my opinion.....typed on my iPhone sorry for any mistakes I hate typing on this thing. PM me if this isn't making sence and I can clarify in detail.