I've got my 2s setup as a single extruder for now.
I've had one successful calibration cube print, but when trying to print the benchy. I'm have issues with layer shifting. at first, I thought it was the belts were not tight enough, tightening them seemed to help, but I'm still experiencing layer shifting.
I think there are two issues, the first is getting the correct tension on the belts. and two, getting the correct motor driver voltage setting.