Thanks Duncan
Mark it's a good question, currently suffering from procrastination paralysis!
The engine has a 1.5mm decomp plate and two 0.6mm head gaskets. I'm using the 9 PSI pulley and so far not taken the engine over 3000 RPM and a boost of 4.6 PSI. The pressure test has all of the cylinders reading between 70-80 PSI, which fist with having the decomp plate in there. Also have fitted a knock sense which needs calibrating as it's over sensitive atm.
So what to do? I'm feeling like getting a professional tuner to tune the engine and configure the knock sense, so at least I have some insurance i.e. if the charge cooler leaks and my inlet temps go too high. But the question is which pulley, the bigger one produces 12 PSI and i feel that with the decomp plate that should be fine but will it be, I don't want to take it to the tuners and come back with it blown but conversely I'd like to get the most bang for my buck (without ending up with a prima donna of an engine)? The other factor is I have an MOT due in October and I'd like to be able to keep the car on the road.
Currently modifying the 12PSI pulley to take the interchangeable pulley system I'd built for the 9 PSI, at least then I can go to the tuners with both options (probably with the 12 PSI fitted) and see what they think, or drop down if it's generating too much boost as neither puller has ever been run at 7000 RPM, although I think that SCs tend to have a linier boost profile I'm not 100% sure...
What I will say is I've really appreciated all of the advice received and happily accept that it is just advice
Also I'm enjoying learning, not just about engines but having lots of fun with the TIG but I would like to make a tour next year!