Re: Height to weight ratios
I don't think there's a formula for optimal height/weight. Like Virus suggest, everyone's different - too many factors to consider. I think as a rule of thumb, most people will say try to get to the lowest weight possible, naturally.
I'm 5 8, and compete at 139 (light-welter). I only drop 3 or 4 pounds to get to that weight. Oddly enough, most of my opponents are still taller than me even at this weight. FFS - i fought a guy that was 6'5 at 139 - but that's pretty rare.
I'm gonna drop to 132 - lightweight this year and see how that goes. Only problem is, I might not be able to look at myself in the mirror.
BTW - you suggested that you feel more powerful at a higher weight. If anything, the opposite is true. The main idea behind cutting weight is to fight smaller and presumably less powerful guys. So you shouldn't be concerned about sacrificing power, unless you are losing weight in muscle, or extreme dehydration. Getting lean and losing fat has 0 effect on power/strength. If anything, it should benefit your stamina and allow you to hit harder in later rounds than a fatter version of you.