If it is an FAC you are after then the 80 is the one. It was designed from the start to operate at about 18~20 ft.lbs. Incidentally both the later AA TX 200 and Prosport seem to work better at their design point of 17 ft.lbs, 99s is a decent gun at well below the 12 ft.lbs, about 10 is the sweet spot for this gun.
A.G