No have not done rings and plenty of compression still (have used other bikes last few years but was my main ride for 10years doing about 6 meets a year and 1 Auzie nationals)will try to get Firko to post a photo.
305 kit, 3 angle valves,larger pipe,mild/medium cam,mikuni,cr250M coil,mild porting a real nice motor.Machined centre entry for carb.Will try to PM photo to you