http://jcem.endojournals.org/cgi/content/full/90/5/2595/F4And yes you should ALWAYS keep your estrogen within the recommended range for males, because anything over that will fuck you up in the long run...
If you get regular bloodwork done and that way can keep check with your estrogen levels try to keep em right in the middle of the range for men...
low range fucks up your joins and sex drive, and has other negative effects...
High range equals, like you said, prostate problems, water retention problems, fat storage, gyno, BP problems all stuff you don't want, and for what? a few extra lbs on the bar that aint gonna help you shit in the long run
edit: if you feel 500iu is working good for you then keep doing it, I'm not gonna be the one to stop you, but keeping the dose as low as possible is the best... Ofcourse it all depends on the individual...
Ideally we should have a pill equal to the birth control pills that women have, just with HCG and HMG instead, would be the perfect oncycle/pct pill