I seated the 300 OTM into the rifling .010". I had ample room in the LA for the long throated 338 RCM.
Since then I have worked up loads for the following hybrids with a jump to the rifling. All were random with OAL determined by magazine length. Only one required tweaking of the seating depth, the 284 win which liked a .025" jump.
6mm 105 in a 6mm-284
7mm 168 classic in a 284 win
308 168 target in a 300 RUM
230 target in a 300 RUM
230 target in a 300 WSM
I suggest you simply choose a seating depth and work up a powder charge. That may be all you will have to do.