Thanks for the reply! I did read that. I do get that I can use the Monitor Out to run it to a power amp. My question is can I do that AND run the Speaker out to another cab at the same time??
I don't see any reason why not ( as you can use monitor outs at the same time) BUT I'd question why.
The sound, just due to the different speaker set ups and relative volumes will be a nightmare to balance, along with any FOH through the main outs.
Your best bet is to either:
1) Get 2 powered cabs the same as suggested - Yam DXR10's etc...
2) get a stereo power amp - matrix seem to be highly recommended
3) Ask yourself do you really need stereo and save yourself the bother. I stopped using stereo many years ago because it did make the sound wider...which is not necessarily good in a band ( depending on music type and number of guitarists) and it can mush it up. Its certainly not louder, just a bigger spread. If you are not loud enough with a 600 watt amp then something else is wrong..
For me, keeping it simple is more effective. a direct sound eq'ed well will cut better than a heavily effected sound ( as a sweeping statement).