Put a low pitch prop on - 13x5 or 14 x5. You will get unlimited verticle with that combo. Mine has a Webra Speed .80 13X5 prop and my favorite maneuver is point it into the wind, slowing it down to a crawl or stationary by gradually applying up elevator to keep her horizontal just over center of runway. Just when everybody is about to comment on how stable she is just hanging there, punch it into a 1/2 second snap followed by straight up out of sight verticle.

Speed is not what this plane is designed for. If you intend to fly it fast seal all control surfaces or flutter will destroy it. You might want to beef up the rudder a bit also. Struts to brace the verticle to horizontal stab is also a good idea. This plane has plenty of wing area and with the flaps I would not worry about weight if you take it easy on the epoxy except where it counts (wing jount, tail to fuse, firewall and landing gear). This model like all Goldberg models builds light.