Seems to me that with the 148gr wadcutter, my load was always 2.5 gr Bullseye. There was a 700X load that worked ok also but don't remember it right off. Got 8# of pistol powder #6 from a friend that died and have been using it with 150gr semi wad cutters. #6 was discontinued years ago.
148gr wadcutters and Bullseye go together like peaches and cream.
Anyone who shoots a sabot bullet has had the problem with loading the next round with a dirty barrel we have all struggled with it.
Between muzzleloader shots I have done some research and testing on my own to find out what works for me for the next shot. I have been using a product called bore butter and when the muzzleloader is just sitting around I leave it caked in the barrel for protection. Have also found that if I lube my sabots with bore butter they really slide nicely down the barrel....