Opinions. Rich cooler temps Lean hotter temps. Its all the same, but location, Barometric or altitude, and drivers style. everyone is differant. Centax clutch it does take RPM to engage. My experience since they came out. 5k+ to engage. I rather have it engage early, 1/4 or less on throttle. Centax works by centrifugal force, more rpm the more pressure. Half throttle much slippage, heat develops, and glazing of clutch material, more maintenance of the clutch.
Life time of engine is a gamble. Had engine last 2 season, running every other week. Racing or practice. Sponered or non-sponsered, professional or privateer. my experiance running IMFRA, ROAR, Thailand, Malaysia, Connecticutt, Florida, California, Colorado. Seen it all, and a privateer. Fun with this hobby