Hi.
I currently have a "pretty decent" alloy bar on the front of my zook.
In my opinion, the alloy bar alone will not be strong enough for a winch without some serious re-design...
As Fatzook has said, you could build a steel cage behind the alloy bar to support the winch... I have been over these options myself, and decided that it was a MUCH easier and stronger job to forget about going down that track, and just get hold of a good steel winch bar instead! I will have my new steel bar bolted up shortly!
ps - your zook might be light, but the Patrols you will be recovering wont be!
Pez