theres a reason for the small teeth Dave-

If you look at most drum robots with similar drums, the teeth tend to rip out of the keyways....my teeth go twice as deep into the drum as they protrude... giving it strength.

Also, if you look at the tips on a disc robot like 360... the teeth are 30mm on that... but only the last 5mm of that actually have any damage to them.

I reckon it'll be ok... might spin it up and drive it into diablo to see what happens when i get chance.