Extended A arms, huh?
I can three wheel my mustang with NO modifications to the A-arm, and I have never 'extended' an A-arm on anything I have installed air ride on. I HAVE sectioned A Arms, and lowered the mounts, but that was for the vehicle to lay a little lower.
Please only talk about things you know about.
You will need a dual action setup. You will have to have a dual action setup, and it is VERY difficult to get a dual action setup with AIRBAGS. Air cylinders are neat little 3 wheel toys, but not originally designed for automotive use.
I like air ride, but given the choice, I would prefer hydaulics. No compressor whine. No amperage draw from a larger compressor. Play all day without the need to refill a tank. Get higher, and lower (generally).