check out this site if you already haven't.
http://www.modernmuzzleloader.com/phpBB/index.php look thru the inline section.
Back before I hopped fence to smokeless and sabotless, my best luck was with Harvestor sabots, usually the black crush ribs, bullets didn't seem to matter as long as there was a good fit to the bore. Cool down time between shots is something to watch for also.