So doing some measurements and the RMC cases I have will hold 35 grains of 2f black or 34 grains of 1f.  I've always been of the belief that black powder should fill the case with no air space.  

These measurements would be about 15% over the old factory load.  Would it be better to back off to 30 grains and use a filler or go with the full case is better.  I've breach seated with smokeless before, but this is my first with black powder.  whats the school of thought for breach seating. 

Thanks