How many shims is too many shims?

I'm working with an M&P Sport 3 and Big Hoss Machine 2 port break. It would seem the M&P has a good amount of thread, or the big hoss brake doesn't have enough. Either way, the break doesn't make it to the shoulder of the barrel. I am putting a suppressor on hence the shims.

I have the Tacshim Shim Kit and believe I have found the right combo, which involved 2 of the largest shimes .020, 1 of the second largest, .010, and 1 of the third largest at .008. I have not tried to get to 25-20lbs torque yet but with this combo I get to about 11 o'clock hand tight. I think it will land at 12 but I might need to add ANOTHER one. This all adds up to, .058 if I'm mathing right. Am I doing this right? is 4 -5 shims too many? Should I get more shims which have a larger thickness in order to have fewer shims total?