I agree with your plan to temporarily put it back to n/a to troubleshoot.
As a test, could you remove the turbo intake and put the oem distributor cap back on? As long as you don't run the car in a dust storm and you don't have
frozen chickens falling from the sky nearby, running the turbo wide open to atmosphere isn't all that risky.
Lastly, have you *pressurized* the intake yet? You do n/a vacuum testing with spray (or smoke), but pressurizing the intake (with an air compressor, for example) is what's needed for a turbocharged intake system. It should be able to hold about 50psi cold. Clamp your air hose adapter in there tight or it will turn into a cannon. (amhik)