Hey Trev,
you need hard on the front and soft on the rear. A good combination would be 50sh up front and 35sh at the rear. I have a set like this but have not yet run them. My current setup uses Jap 52sh up front and Mardave pink mediums at the rear, but I think the Contact tyres will be even better than this.
For pinions you only need a standard boss. Long boss isn't necessary. The bore must be standard (1/8"), not 3/32" (2.35mm) as this will not fit on the shaft of a 540 size motor.
DAVE
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