Lee there has to be more to your lack of power(unable to get power) problem than just comp ratio. A local lad round my area has the same turbo as you and on a std inlet is running 398 on 1.4 bar,i'm not 100% on his comp ratio though but i'm pretty sure its still in the 8's. How is he able to fit the boost in without det'ing?
Robbies LET made 530 on 1.2bar(gt35r) and Adaptec made 400hp on 7psi. I'm sure the LET is just as good for big power as the yb just seems everybody prefere to use what be tried,tested and race proven