I have the hydrant slug mold, the paradox mold, both lee slugs, lyman 525, numerous round ball molds .662" up to .690" and to be honest for ease and cost I would chose the lee or a round ball.
The mold and was combos from Russia have proven slightly more accurate than the plain old wad slugs.
They will stretch accuracy out to about 75 yards if everything is perfect. If your wad gets crumpled shifted or anything during the seating and loading process all bets are off.
With my pet load with either the lee 1oz or round ball loads I can get about 4" groups at 50 yards consistently.