As long as this isn't illegal to use a double ball, then that is an excellent idea. Some states specify only a single projectile during muzzle loader season, BUT if you're not doing the hunt during that season, you will be fine. Consider if you would feel comfortable with that weight in a single bullet, and say an 80 grain (3 dram) charge of 2Fg? Well those two projectiles, as mentioned will land near to each other but not together and should be expected to do more than 2x the damage that a single conical at 360 grains would do. Should hammer a black bear. (as Curator mentioned it was called "loaded for bear", and it was a serious technique before Hollywierd made light of it) Shouldn't be a problem in the barrel of a modern made muzzle loader. (In fact in the early days Thompson Center used to publish data for double-ball in .45 caliber as they didn't understand that the .440 round ball was fine for deer as a single projectile).
LD