That's interesting because my experience has been going to a *heavier gage* allowed me to lower my action. On my Strat, I experimented with 9's and a lower action. I had some fretbuzz, but I also felt like I wanted to move to 10's. Moving to 10's resolved the fretbuzz. My understanding is that heavier gage string have more tension, therefor they travel less (vibrate in a narrower patter) to produce a given tone. Because of this, a heavier gage allows you to lower you action more.