Info threaded did not respond to the OP question in a positive way.
Sounds as the OP is very satisfied with the accuracy of the sabot combo he is using, just not the hard loading. Having been down that road, IMO, switching to a different sabot would more then likely be an easier process to attain the same accuracy with easier loading then switching to a full size conical in which he'll have to start all over again finding the 'sweet spot' for his rifle and probably loose a bit of accuracy in the process.
FWIW, maybe there are those that have, but with inlines, I've just never been able to get as good as accuracy out of full size conicals and maintain easy loading as I've been able to get out of sabot rounds. Not saying you can't get 'deer accuracy' out of the full size conicals. You can!
I've got two inlines that shoot full size conicals with great deer accuracy, another that shoots them okay and yet another, which happens to be a T/C that doesn't shoot them well at all but will clover leaf sabot rds at long distance if I do my part.
There's one thing that all four of these rifles have in common...all of them will shoot sabot rounds of the right combo the best(especially at distances of 100yds+) and with the right bullet matched with the right sabot, I don't have to use a jackhammer to load them.
Again, for the tightest, consistent grouping out of an inline, it would be my suggestion to stay with the sabot round and find an easier loading sabot.
Are you finding the rifle hard to load from the very first shot in a clean bbl. and are you sure there is no plastic fouling buildup in the bore?