I don't have any loading data for .41 Mag handy. But from my experience with my win 94 in .45 colt I am able to spit out 300gr hard cast gas checked bullets with Winchester 296 or Hogdon H 110 at an average of 1750 fps. You should be able to come close to your goal with either of these powders with careful load developement. A plus with these powders is that they are very fine and meter exceptionally well and occupy a lot of case volume so you probably don't have room for a double charge.
edit.
I almost forgot, these powders require magnum primers for consistent performance.