Since you have a LRMP module system and centerfire receiver its well documented. No need to duplex with that setup but N110 is a great booster if you wish. Remove 10gr-15gr from main and replace with 10gr of booster.

Dont go over 70gr of IMR4198 (or total powder weight) for bullets upto 275gr and you should be just fine. I stop at 65gr with a 300gr bullet in my Savage small shank. That is plenty to kill anything with hooves in NA.

Parker 275gr Ballistic Extremes are crazy accurate sabotless. One of the easiest bullets to get to shoot. They should load with roughly 1 hand loading pressure when sized correctly. An adjustable sizing die will be a HUGE help getting bullets sized just right.

Just for reference, Hankins LRMP system (HIS) 66gr of IMR4198 and a 275gr bullet is right at 2600fps and a 300gr is slightly under that. A little more if you have a 28" or longer barrel. So as you can see, you are well into 458WinMag territory.