For my only brasser (Pietta Griswold .36 - the first one, almost six months now) the loads are kept low at 16/17 grains and at that level of charge a heavier conical never seemed justified. A potential squib problem is concerning, too.
So, having never done it, my opinion lacks any basis in background or experience. Ill stick with round-ball though and conserve Navy size conical for steel frames, especially now in view of Hawgs observation.