Another option is Dick hanson's Runaround series. They are typical construction of foam and glass and he makes them sized for the YS91 (large wing) and the OS91 (Small wing). I built one 4 or 5 years ago with the os91 and it came in at 7lbs even. I'm building another currently with a saito 100 and it's at 6.0 without paint or monokote. It flies well enough for the first three classes.