I need help with the low pressure side-- I plan on using a 1' long piece of black pipe, a couple 90° fittings, and a brass adapter to go from 3/8 NPT female regulator output to 3/4 black pipe. However, I have not been able to find that specific brass adapter. Anyone know where I can find one?
Is this what you need: http://fittingsandadapters.com/adapter.html - part 23212x6 ? If you're in SoCal, McFadden-Dale probably has them in their stores, and if so for much less than the online price. You may also want to think about having a valve immediately after the regulator, just in case . . .