I think the easiest way to check the tune up on a methanol engine is to look at the exhaust valve on #6 cylinder (SBC).
A very light tan color is usually pretty safe. If the valve is white, that is too lean. If the valve is brown that is too rich. If the valve is blue you are probably in deep trouble.
Sometimes the port is hard to read due to idle circuits, racing conditions, etc. But if you look in your header there should be a slight trace of carbon in the entry to the header pipes and no soot at the exit. If you have black carbon soot at the exit of the collector you are too rich.
Anymore, at least in circle track applications, it seems like detonation caused by a lean condition will crack pistons under valve reliefs before they will burn the edge off. (Voice of experience speaking)
Several pistons were harmed during the testing of our products!