Turbo function checking is pretty straight forward. You've just looking for boost. The pressure increase should be smooth. You should see a peak value achieved by about 3000 rpm when floored under load, and it should stay close to that peak all the way up to redline.

At this point, I wouldn't be worrying very much about it, and I certainly wouldn't go flogging it if it's really pinging badly. That's a dandy way to blow a hole through a piston.

I doubt your problems are related to the turbo. More likely you're not going into open loop mode, wrong static ignition timing, etc.