OK, my settings are 22% SET, 7% GAIN, SET GAIN is set to 9psi.
22% SET gives me 12psi. The thing to remember is that GAIN not only affects the boost curve (you use it if you are tapering off or spiking) but it will affect the overall boost (as you increasing gain you will increase overall boost so once you get it holding boost nicely you will need to lower the SET value).
It is a good idea to only go a little over base boost to start with, then get it holding boost nicely with the GAIN setting, once it holds boost you can pump up the SET value a bit.
So now you have it running the boost you want it's time to play with the SET GAIN value, as mentioned above, this is when it will open the wastegate. You basically keep increasing this value in say, 0.5psi increments until it starts to spike (i.e. will say spike to 13-14psi then sit at 12psi) then back it off 1psi or so. You are essentially trying to find the fastest spooling time without it spiking.
Hope that makes sense.. I literally just woke up!