#2
Stereo only applies if you have a head capable of producing a stereo signal. Basically you match the impedance of the cab (4,8 or 16 ohms) to the corresponding output of the head. Most amps will have one output of each. My TSL has one 16ohm out which I use because my cab is 16 ohms, then 2 4/8 ohm switchable outputs. If you're using more than one cab its different though, I dont know about that because I only use one cab.