Beetleweight Spinner

I'm in the process of designing a beetleweight vertical spinner but was wondering how do you go about attaching the pulleys to the motor?

I don't know how strong it'd be but get a shaft with a D shape profile, locate the pulley on the shaft and use a grub screw to hold in before drilling an indent for the grub screw to sit in. I'd also lockthread it (the pulley entirely) onto the shaft to further hold it in place.