Well, there's lot's of variables at play (wind, wave, current, tide, boat load, perceived comfort, desired speed, etc, etc) and there's really no "one best" trim setting. But, generally speaking, for "hole shot" you want the engine trimmed down to lift the stern as quick as possible. Then, as the bow starts to drop back down, trim up a little bit at the same time as you're pulling back on the throttle. For running in chop (assuming you're going for comfort, not speed), what you mentioned is correct. You want the bow to be breaking the waves. Think about it - the V at the bow is very steep, while the V at the stern is much flatter. Which one would cut the water better?
Now, if you trim down too far, and push the bow down too much, you're adding a lot of drag by having too much boat in the water. Two main things can happen: You will quite a lot of speed and have to run the RPM's higher, and you could experience "hull steer" where the boat actually starts to list.
You have trim tabs, right? Don't forget about those! They also have a tremendous effect of the boat's attitude and can help to keep the ride comfortable - even more so than the engine. Plus, they won't drop your speed as much as compared to when you have the engine trimmed down. But get used to the boat and the engine trim before you start learning how to use the tabs.
Bennett's site has some excellent "how to" info for tab usage.
