For new construction, I recommend an IntelliFlo VS pump and the Intellicenter automation. A single speed pump is not a good choice.
A whisperflo is a horrible choice for a waterfall pump. A whisperflo is a high head pump and a waterfall is a low head feature.
Pentair makes pumps specifically for waterfalls that would be a better choice. They run at 1,725 rpm with a big impeller, which is a better design than 3,450 rpm and a smaller impeller on a Whisperflo.
For a waterfall booster, go with a water feature pump or an Intelliflo XF.