Stan, what's the purpose of the shaft extension? I'd think just using the switch as it is would fill his requirement with the resistors. Are you thinking about the transition between points? If so, a shorting rotary switch has make before break contacts and would probably do the trick without the mechanical trickery.
Ceramic Rotary Switch 2 pole 11 positions (Make-Before-Break). NOS. Lot of 1, eBay: 264169120324
A little more expensive, but a lot easier to get working without mechanical issues.
