Joe6Pack,
I'm sure Big C CamLock's work great with 1/2" Si tubing, I recently found that a friend in Florida uses them, and is very happy with them, but if there's little pressure drop with the simple 1/2 barb, I'm going to just go for them.
Thanks to everyone who responded, and I hope this discussion has helped more than just me. So much of good brewing is knowing which variables are important, and which can slide. This is one more small lesson.