Booming down with a heavy loed

Any advice on booming down a 500-T Lima with a 85% load? Straight boom down with engine @ idle gets faster than I like and makes for an uncomfortable stop! Tried booming up position with engine idleing hoping to back up converter reversing geartrain like it does when hoist down with heavy load but that diddent work, The boom still raised. Boom down & Hoist up works for short shots but even with 6 parts in the hoist it still overruns the boom. My riggers and myself appreciate any help with this!!

Booming down with a heavy loed