[OXO cube]

However, it might work better if it was a 2 stage step down to slow the wheel speed , reducing oil spit from the tyres.

noted , 1st time use , i was liberal with the oil , big mistake 
oily glasses , clothes and face is not good 
even with the adjustable power supply turned down to the minimum , the speed is too fast 
i even turned the axle over , so that the top axle runs backwards , to create an oil pool at the nip point 
this minimizes oil spit / fling , but the speed is still too fast 
so you are correct alan , it needs gearing down some how , ideas welcome

for the wheel balancer , i too thought of the micrometer Mazda
but 50 - 75 mic's can be expensive
the only problem i had with the current design , was getting the free end distance correct ( easy with the micrometer )
this is critical for a free turning axle  
but once this distance is correct it works great 
btw , the tyre wheel pictured were for display only and weren't trued etc ... which is obviously a must before balancing 

Kev