If the comp cam tech took all the numbers you posted here and looked at what the dynamic compression is with your cam and said 11.3:1 would be the max static compression I would say that is a pretty safe recomendation. They won't give you a recomendation that is on the ragged edge.
Bigger cams typically close the intake valve further after bottom dead center (ABDC). The latter it closes the shorter the effective stroke is and the lower the compression. i would use the calculator on the Keith Black site and put in the intake closing point numbers of the cam you are using and see what you get for dynamic compression. Moper would have more experience if that number is likely to give you detonation issues.
When I built my engine I did it with a "it should be Ok" mind set but was prepared to swap to a bigger cam if I needed to bleed off some pressure or even to swap back to the LA open chamber heads.