How many guys and how much gear and beer in the boat will also make a difference on how well the boat slides too.

But seriously, if you are new to a driftboat and all things are equal, such as your boat, load and weight distribution, you will naturally tend to overrow anyway. Time and experience will significantly improve efficiency. There are of course some tricks to conserving energy and knowing your boat well enough to save some strokes but these produce relatively minor changes. The boat and how it rides makes the biggest difference and there is little you can do about that.