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
Its hard to go wrong with shocktech. I would go so far as to say the shocktech sfl cockers are the best on the market. What shocktech parts would I recommend, easy all of them. What I look for in a bolt is evolution style pull pin this the best design out there. It should have good flow characteristics, and the back part should be wide and long so that even in the cocked back position the thick part of the bolt is still in the body, and will not allow the back block and bolt to wobble. There was a bolt out for the autococker I think it was called hourglass shaped that just had a wide part at the head and tail and the bolt would chew up the body because it would wobble as the gun recocked. It should have been a crime to make that thing!