Dual tap kegerator. One for micro beer (starting with a stout) and one for BMC. Should I be using a single regulator with two air release ports or use a double regular so I can regulate each individually? Not sure if my required air pressure will vary to much?
IMHO you need the dual regulator. The pressure will really vary by style of beer. It doesn't have much to do with micro/macro.
As with many such questions, it depends. Two regulators are certainly more flexible, but unless you plan to serve beer that is differently carbonated, it's overkill. 95% of American beers will happily survive at 12-ish psi. Unless you plan to serve the other 5% at the same time, a single regulator will do the job. On the other hand, $35-ish is not a helluva price to pay for 'just in case'. (FWIW, I have 4 faucets with 2 regulators)
For a comprehensive read on serving lines and pressure you can go to http://www.draughtquality.org. There's a PDF on that site that you can download called the Draught Beer Quality Manual. There's some math involved with regard to the diameter of your serving lines, length of lines and the height of the tap above the beer in the keg. Basically you want to maintain the level of carbonation in the beer as you draw the beer out over time. Ideally a pint of beer is poured in 8 seconds. At least that's what I was told by a guy who owns a tap line cleaning service. So shoot for a pressure that gives you approximately that rate of flow. You could start at 10psi and work your way up if need be. Watch for bubbles forming in the line, you'll want to increase the psi by 1 and check for bubbles. And of course check for leaks...
I'd vote for dual primaries, if you foresee a wide variety of beer styles. I have a dual primary, multiple distributor setup in my keezer, and sometimes wish I had a third primary regulator.
You could go with a single with a T and add this later if you find that you are serving beers with wildly different serving pressures. I have both (I do a triple cornelius in my kegerator). I usually have at least one beer that is different enough to justify it.
