If you have an autococker question post it here and i will try to help you out. I will also be setting up a cocker tech page with FAQ and stuff like that.
http://cockertech.homestead.com/cockerhomepage.html
There is really no reason to have anything over 12" just ask any chick. try shooting them both if you can, and see how you like them. i would go with the lapco myself as i said before.