Building A Brew Stand

I just received 2 new 32 tip propane jet burners for the brew stand I am designing, and was wondering how far away from the bottom of the pot I should mount them. I couldn't find the spec on line but it was suggested to me that it should be 12". That seem excessive. Anyone work with this type of burner before?

http://i.ebayimg.com/t/Jet-Burners-32-Tip-Cast-Iron-14-32-Brass-Nozzles-New-320-000-Propane-/00/s/MTIwMFgxNjAw/$T2eC16JHJHQE9nzEyP!zBQifiHBf2g~~60_14.JPG

On the banjo burners the rack is about 6 inches from the burners. Not sure if that helps, but....

I was thinkin' 6-8". Thanks