The problem you would run across changing gauges is that it will significantly change the feel of your racquet. I went from 17 to 16 gauge once...not good! It made the entire stringbed feel way too clunky for me. The only benefit was I didn't snap a string for like two weeks (I usually broke some 17 gauges in about 4 days), but it was definitely not a good tradeoff based on the change in feel o fthe racquet.
The best bet to lowering power would to be increasing tension. This will also make your stringbed feel more solid, but it won't necessarily cause it to become "clunky" like a string gauge change would. In fact, this is probably the safer bet since you're still using the same string with only a difference in tension. If you do choose to do this, make sure you only go up a couple of lbs of tension at a time and keep going until you get it right. I recommend this instead of jumping up like 5 lbs because it helps you keep up with the feel of the racquet changing with the tension so you can figure out exactly what you want to do with your stringbed.
