try to take several pictures !!!
i also bought some parts from ck burners, trying to get all my parts together. if you need a retention head i just got one on ebay, i thought it was a good deal???
http://cgi.ebay.com/Clean-Burn-Retention-Head-Slide-Over-/200543450729?pt=LH_DefaultDomain_0&hash=item2eb1523669
Got some before, got some after pix. Just don't know how to post them.
So far it's been very simple to assemble no big problems. ckBurners are great to deal with. The Sunday of Thanksgiving weekend I was assembling the heater block and needed some information. So I sent an email to ckBurners thinking I'd be first on there list Monday to get a reply. To my surprize they replied that afternoon.
Had a junk stainless steel microwave laying in the scrap pile, so I've made my own retention head. Also had made a retention like the style you bought, but I wasn't happy with the way it came out.
Finally picked up a burner control with 15 second safety switch.
Just need to wire up the heater controls and I'll be good to go. May try to and test fire it this weekend without using the block heater before I go any farther.