Just my opinion, but in a lake that shallow there are no real advantages to having the extra 2000 watts. In some cases the extra power can cause some problems reading in shallower water. I've got two units I'm running now, one at 1500 watts and one at 3000 watts and both do great in the depth range you've stated. I don't think you'd have any problems with the 2000 watt unit for the circumstances you've stated.
-T9