Just treat it like any other chambering. In step 4), adjust your FL die (I prefer Forster) to bump the shoulder 0.002-0.003”. Done.
^^^^^^^^ This ^^^^^^^
I started loading for belted cartridges in the early ‘80’s, before the internet was around to “make mountains of mole hills” and with assistance from a Lyman manual from the early’70’s. Due to my youth and inexperience, I followed the same procedures as I had the previous 15 or so years with non-belted cases!
In spite of myself, I managed to get my old Model 70 .375 H&H to grant me a few sub 3/4” 5 shot groups @ 100 yards…..with one group going under 1/2”! memtb