Not an expert (far from it) but am planning my build and have been spending a lot of time looking at others equipment.
I like jcdillin's setup, using these : http://www.mcmaster.com/#8239k26/=47aekp
Found in this post (see #11 for part list wtih active links).
This is a fairly inexpensive weldless system.
Where did you get the coils if I may ask?
CRAP, I was thinking HERMS heat exchang coil inside a HLT.
What are you trying to connect to specifically? Some of the people here have a near encyclopedic knowledge of the mcmaster-carr catalog and can steer you the right way.
Sorry not to be of much help