adding an effects loop

[mhartington]

So I posted a few days ago about a pedal board project I'm planing and in my research I have turned up more questions and ideas. One thing that i want to do is add an effects loop to an already existing distortion pedal. I want the pedal with the loop to be the main source of tonal colouring.

I thought an actual loop pedal would be a good place to start looking but where exactly to have the circuit go? One loop on the GGG website uses a 3pdt switch, would a 4dpt switch be necessary?