If you have hours left to build, then don`t waste them. Everytime you go flying do something constructive. Be strict with nav..eg...Try and fly +/- 50 ft and +/- 10 deg. Take an Instructor up for an hour and see if there are any holes you can fill in. Better to iron something out at £12 to £15/hr than when you get on your CPL and pay £75/hr for the Instructor.