Honestly, I've read quite a few debates over the "best" setup for tanks and/or compressors. I can tell you what I've done in the past and hopefully it'll help.
I've had 2 electric compressor setups and one edc (engine driven.) One setup had 2- 5gal tanks with a single Thomas compressor. One had 2- 12gal tanks with 2 Thomas compressors. The last was 2- 12gal tanks with the edc (burned up the Thomas'.)
I would say, it all depends on what speed you want. It's easier to build a setup and "neck" it down slower than it is to speed it up (depending on pressures.) With the 2- 5gal setup, I had a manifold with 3/8" dot line. Running a heavy front end, it would turn on the compressor on the second lift (of just the front.) The 2- 12 gal compressors had 2- 1/2" id lines to each front bag (same car.) The first setup was @175psi. This one was @ 145psi (175psi was too crazy and the fill time was nuts.) The compressors would kick on during the 3rd lift of the front or 2 front 1 rear (if that makes sense.) The edc was used after one compressor cracked the head.
Personally, I'd run a smaller tank, higher psi, with a faster refill rate. An edc is one of the fastest refills I know of (other than an oasis, but same concept.) There's a million ways to skin this cat, but from my experience: good parts, minimal leak/failure points, and simplicity have made all the difference...
(hope my rambling was understandable, lol)
