I'm not the expert. But based on what I've read, a 3/4 hp two speed pump is probably what I'd get if I were in your shoes, especially since you have 1-1/2" piping. The variable speed control units are, apparently, very susceptible to power surges. Pool rated surge protection is highly advised by the experts here if you go that route.

This is a good read.
http://consensus.fsu.edu/FBC/Pool-Ef...on_systems.pdf

Maybe an expert will chime in.

Pappy