Rather than level the boat, what you want to do is level the hub (straight up and down). Then you can set your blades to the desired pitch.
I used a regular angle finder becuase I didn't have the Warp Drive protractor. It works just as well. If you use one of those, you can actually set the pitch without leveling the hub; just find the angle of the hub, and add/subtract it from the reading at the blades. Just have to pay a little more attention to what you are doing that way.
And by the way, Warp Drive blades don't all have to be perfectly at the same angle. I have run mine as much as 2 degrees apart on a 5 blade and did not notice any vibration, so get them as close as you can and don't worry about it after that.