volume pedal is a smart idea. I might do that.
The right cables is the trick to it though.
Here are some Hosa Cable options
3.5mm to 2 1/4" TS
Model Length MSRP
CMP-153 3 ft $8.60
CMP-159 10 ft $12.30
HMP-003Y 3 ft $16.65
HMP-006Y 6 ft $18.00
HMP-010Y 10 ft $19.95
Then a 2 pair of 1/4 TS - 1/4 TS
I use a Keyboard cable that essentially is 2 1/4"TS to 2 1/4"TS. But, I've also put a pair of instrument cables together and zip tied them every 10 inches or so. If you do it that way you can use 2 different colors to designate left and right if that matters to you.
Also check the pedals impedance before you buy it. I know this matters but I don't remember what is correct/best.
The volume pedal also gives me the ability to lower the volume on tracks that are too loud. After a while I start to take note and redo (normalize) those tracks on the computer.
I suppose I could use a single cable and let the 3.5mm TRS end of the cable sum it into a single mono 1/4" TS. But, I just don't like the idea of combining a left and the right amp output together via a cable.
Or, if your PA/Amp has 1/8" input just use 2 of the 3.5mm to 2 1/4" TS cables. One into and the other out of the pedal.