I run 35-40 psi with a 205/40 on an 8 inch wide rim. I ran about 40 psi when I was running a 205/50 on a 9.5 inch wide rim.
I have never had problems on either, personally I stick to the 40 ish psi mark. Its what I have found to be a safe bet on my setups.
With your set up 40-45 psi is what I would recommend, but I've never run any profile smaller then 40 so far.