I'm not a huge 'pistoleer' nor do I shoot many straight walled revolver rounds in the Handi, but I would need more info before answering your Q!?
I've been reloading for over 20-30 years, and would be reluctant to swap data from one round to the other!
Keep in mind the .45C +P operates at 21-23K units of pressure. Std .45C around 17,000-19,000 units of pressure.
The full-house .44Mag loads approach 35,000 - 37,000+ units of pressure!
Trying to load a .45 Colt to mimic a 'hot' .45 ACP load would seem much safer, IMO.
But what gun are you planning to use your 'special' .45C loads in? Is it a modern gun with modern steel and metalurgy?
Why do you need that stout of .45C ammo? Have you checked Paco Kelly's board? He praises the +P .45Colt. But doesn't 'mix' it with the .44Mag!!!