Rechecking I got the 0.00299, but multiplying by 60 to get per hour works out to 0.13794 rotations. Weird.

I do like the idea of using mass drivers for spinning up the Ring. More elegant (and less radioactive) than the ion drive, and with a little wiggle room built in they could probably be used for station-keeping.

Actually they're part of the design already, figuring in the transfer system to move things to and fro between the beanstalks and the Ring.