1. Buy the book, I need to also.
2. Reload, because you'll need to work up some low pressure loads. Hodgdon lists CUP for their loads. Here is an example of how wide the pressures can vary, and thus, you can take advantage of it: 180 Sierra with H4831 - 44,300 cup 2710 fps and Varget 50,000 cup 2668 fps. WOW 11% lower pressure and 42 fps faster. Of course these are max loads and therefor you should load 10% lower. I do this with my .375 H&H and am in the 40,000 to 45,000 cup range for all bullets weights. Still well bellow the factory loads of 50,000 + cup.
3. Don't fuck with your rifle. You will be able to sell it for what you paid. Except light aircraft, I've never seen anything you use and still get what you paid.
3. Be paitient, Experiment, keep maticuless (sp) records, and have fun!