Thanks for all the good input Drado and Greg. I ended up getting everything tuned pretty well, but for me, it was a lot of trial and error. I'd remove the diaphragm on the MR-12 and adjust and then repeat the process until I was fine tuning at about 1/16th of a turn. The MR-12 II I picked up, is a little less finicky. At least, that's been my experience.
I've dove the MR-12 a couple times now, and it's smooth and easy, but I'm not getting the warm fuzzy feeling that this is the best reg ever. The MR-12 II, seems to breath a little bit better.
On a sad note, I've only breathed the MR-12 II underwater very breifly. Last weekend I had plans to dive it, but was called just before the dive by my buddy, who informed me that her reg(an Atomic) was blowing bubbles out of the 1st stage somewhere and that she needed to barrow a set of regs and a drysuit hose. So, this is what she got.
We were diving in the channel again to look for bottles and steamship china. The only logo I found was on this broken bit:
Found a cool cork stopper elixer bottle, possible even a bitters bottle:
Overall, I think the MR-12's are working well, and my buddy from the other night, says she thought it breathed well, she didn't even notice the leak in the air hose.(A Scuba Pro replacement)
I do not believe in taking unnecessary risks, but a life without risk is not worth living. - Charles Lindbergh