Very high oil consumption via combustion can be easily detected by running a finger round inside the tip of the tailpipe. A finger wet with oil is proof the oil is running through engine internals trying to be combusted.
Blow-by past the top compression and 2nd piston rings will pressurize the crankcase causing lube oil to vent out of crankcase access holes. High blowby defeats the operation of the bottom oil ring and encourages much higher oil consumption.
The 1st thing I would do is a wet/dry compression test on both cylinders. A cylinder leakdown tesr is better but it takes an intelligent tech to perform a leakdown test.
