Safe High Salaries and quality output

Whats the safest high salaries can we have and the highest quality output?

Thank you.

I usually put mine at 400 to 450, and you might want to increase your welfare index by improving all your indexes (Transportation, Health, Education, etc), with mine at 128, I usually get my corps at 125+% production. Also, put your government salaries at 350 or 400.