Hehe, no need to thanks someone over a year ago. Thats a pretty stale cookie you give them. Anyhoo, yea lots of info in this old long running post.
Most of us like the look of 3/4 OD 1/2 ID, but if you want to run 3/8 ID, then no reason not too. Keep the wall thickness at no less than 1/8" each side or if you have really bent tubing runs it kinks pretty easy.
You picked good stuff in the PM you sent me for tubing.