Way ahead.
Have half a dozen. Xotic clones, a Klon clone, and 2 Kokko boosters that make gorgeous toan. I had been experimenting manually between pre and post locations and wanted a less tedious approach. Meanwhile the Xotic clones are amazing overdrives besides boosters so obviously I must look into AB ing them in the same chain. I figured an ABY pedal would do it but they don't come with a proper summing cable nor have I found any to purchase. Hence this thread.
I retired my Yamaha tabletop mixer in favor of a Behringer Mackie knockoff but that's in use being my home stereo preamp. (kills incidentally)
The other thing is I have this notion that putting a mixer send or bus into the front of my amp will suck.