If your sticking with existing motor, get yourself a tiny tach to get your rpm readings. Then you can tweak your prop selection. Also look at motor height - in relation to the bottom of hull and cavitation plate. That can make a difference in performance.
Try and avoid the hydrofoil/Wale tail if you aren't having significant planing issues. They generally sacrifice top end speed a bit for the ability to plane better.
Do you have the 162 pro series tiller?