I use about 5 lures, i think you can capture then when they have a potent of 130, i think...
I think one less lure could do the trick. I capture every creatures (include rohusk and bernard werewolf) with only 4 and don't let the effect less than 90 turns. Be sure to drop their health to almost gone/ raise the libido to almost full, use the lures and do the last action so the turn won't drop much