Would this be how the Dry Out switch is done? Potentiometer’s leg 3 is lifted from the pcb. On Dry Out 1 and 2 are shorted. On mixed Leg 3 is connected to Pad 3 on the PCB.
If that's all you want to do, all that's needed is cutting the connection to lug 3 on the pot; the left side of the DPDT switch you have drawn is unneeded.
Better yet, put R1 on the switch instead. It will kill the dry signal just as effectively. The benefits are
You can still use pcb mounted pots.
You don't have to mess with wires to the potentiometer.
R1 is off to the side and near the enclosure and should be less prone to picking up square-wave bleedthrough.
The downside of switching R1 is that you might hear the footswitch click.
Either method will be fine. Personally I would do R1 and run the wires to the footswitch on the left, and be very weary of picking up electronic noise from the logic chips. Those chips are flipping a square wave at over 10x the amplitude of your guitar signal, and it's so easy for wires to pick up the sharp corners (harmonics) of that square wave. I learned this the hard way by modding a MIJ OC-2 man years ago. The circuit would buzz even when bypassed.
If you have a way to cut it at the red line, that might be less noisy.
If the pop is bothersome, your next best option is to just disconnect lug 3 from the pot.
You figured that part out yourself, you just didn't need the left half of the drawing.