WELCOME TO TFL!!!!
Unfortunately what works in someone elses weapon, probably will not do well in your weapon. Generally, the 300 H&H, like most other large capacity cases, will shoot more accurately at or near max loads.
I have found IMR 4831 to be an excellent powder for accuracy and velocity. The 200 grain bullets will perform better.
The bottom line is that you need to develop your load, by working up several bullets and powders. If you use the dartboard approach (trying to use other's pet loads) you may, out of sheer dumb luck, repeat, you may get an accurate load. However, I would bet against it.