If rules read:
You May sand off mold markings only.
You May not sand or alter the hub surface length.. (inner hub?)
You May not sand or alter the surface or edges..(tread surface?)
What outer wheel hub modifications might you try doing with the double recessed hub
to gain a little more speed out of the wheel or to help hold the lube in the outer hub.
And what type of axle head modification would you use for your wheel hub modifications.