The best sound results from shortest signal path. So let's keep volume, selector and signal wiring to/from inputs/outputs short and at the back of the chassis. That means shaft extensions are needed. Have you ever tried them? They do the job but sometimes with a poor tactile quality. The problem is the way the shaft connects to the switch. The Uni-Flex Joint solves this.
The Uni-Flex is 23mm long x 18mm diameter. As it turns it adapts to the angle of the rotation axis and provides some mechanical decoupling from knob to switch.

Set includes:
1 Uni-Flex Joint
1 switch mounting bracket with adjustable height 10 - 50mm and positioner slot.
1 aluminum shaft 240mm long x 6.0mm diameter. You can cut it to length. Solid aluminum.