Whats the best rpm to split down and best rpm to take a full gear out while pulling a grade in these new emissions engines to maintain full power

In my old 700 6nz i used to not let it fall below 1650 before a split and 1500 before taking an enitre gear. Too low an rpm the pyro got hot super quick

I heard you can let the cummins x15 lug lower than that but i couldnt imagine thatd be great on the exhaust system.

Boost guage says it maxes out 32 psi at 1500 on a 625hp tune but doesnt seem to like to hold power lower than that. 🤔

It seems to not need as much boost to hold max power as an old CAT.

Can anyone explain this to me? Give me any tips?