I want to try running my JMP+JCM 900 through my 1960A cab. I know when using two separate cabs there can be the problem of one of them going out of phase. Can this also be a problem when using 2 heads into 1 cab? I have a radial big shot ABY pedal that I plan on using to play through the 2 heads at the same time. The pedal has features to prevent the ground loop/phase problems. So far I know, when setting up the two heads to the cab, is to set both heads to 8 ohms and select the stereo setting on the cab. I'd just like to know the proper way of going about setting everything up. I don't wanna ruin any of this gear.