I use Swiss fff for most everything now a days, from 32 to 62 caliber rifles, and even in 12 gauge with success (although I have a double that may be favoring Swiss f). You just have to find the load that makes the gun happy. I find it simpler to stick with one powder and just vary the charge for each gun. Once I settle in on a load for a gun I may make or get a fixed powder measure or two for it.
When trying different powders found that most would have at least one, if not two charges that would work with an individual gun, patch and ball combination. Sometimes different powders shot the same with the same charge, but most times not, especially by the time you got to a 100 yards.
Years ago I was given a collection of powders from different manufactures with a variety of vintages by a buddy of mine who's uncle had passed away. Buddy didn't shoot black powder... Collection had multiple ff, fff and ffff powders. Could get most of them to shoot accurately, just not always to the same point of aim or with same powder charge. Point is, as others have mentioned, you should be able to get the Swiss fff to work fine with some load development. Actually think that is one of the fun things to do with a new gun. Also agree Swiss is a little more energetic than most other powders.
Wish I would have kept all those old powder cans. Saw this post just before I was getting some powder out, so lined up a couple of containers, both old and new, and took a photo. Also interesting to see some still with the original price tag on them. $2.10 for a pound of powder....
