There are folks that use 3F in 45-90's. I use 15 gr of 3F under 92 gr of 1F in my 45-110.
The only real no-no in a cartridge is 4F or finer (if there is such a thing, or someone makes some),
I have shot 85 gr loads of 3F in my 45-90 Shiloh.
It truly is about the accuracy. Most folks use 1F in 45-100's or above
2F in 70's and 90's and 3F in smaller cases.
Folks use Swiss 1.5 in 70's and 90's.