I believe that More critical perk(@9) is not good for slaver, becouse you might kill slave with critical hit even if you want him to knockout(best is 1% critical chance), but "even tougher" perk will make you invincible for Rave partys, which are best source of slaves, i suggest you to take this perk on level 9.
If you are planning to do slaveruns with your slaver, you will need do much more damage. In case you dont want kill slaves, you should minimize your Critical Chance, but maximize damage you can deal per turn. With Fastshoot, Bonus Rate of Fire and at least 10Action points, you will be able deal 100-150 dmg per turn.
Good luck, i like new slavers in game
PS. Sorry iam not from poland(Used google translator)