Good points, smylee grouch. I found back in the 70's, I got better accuracy with 2F - than 3F in GO, C&H, Dupont, Meteor, etc, in my .50's.
It's still my go-to powder for .50 and up, however I did work up loads in the .40 and .45 with 2F as well as the normal 3F I was using in those.
The accuracy loads with 2F, consistently required 10gr. more powder, than the 3F accuracy loads.
I have not tried Swiss powders in my ML rifles, however do use it (1 1/2F) in a suppository-rifle.
I also have some Old Enisford 3F to try in the .50.