The hot spot I showed you was a powered unit, so it CAN run off the back of the eon, and if you can't hear the mains ..... even if they're not in your face - something's wrong. A monitor only has to bring the signal closer to you .... not make it concert volume.

As for using one eon - I only do that in small, tight situations. The eons don't have much bass by themselves, and if I can only have one speaker .... chances are, I'll take the woofer and use the kb speakers as full range tops. (I did just that tonight)Unconventional useage, I know, but it works great. Adds punch and bottom without excessive volume. An eon alone can't do that.
Mono/stereo? That's a situation call. It makes little differance in most places. The one who benifits the most from a stereo mix is the player. The audience usually suffers if the speakers are spread too far apart. It creates holes in the sound blanket around the room. I prefer to use stereo, but I won't compromise the correct blend for the room just for my comfort. that's why I insist on stereo monitors in my face (kb) The monitors are always set for MY comfort, and the mains are set for optimum audience coverage.

The whole monitor issue is very personal. Some acts don't seem to need them at all. Watch the Ed Sullivan tapes of the Beatles - not a PA in sight, much less monitors, and who could hear over Tom Cavanaugh and his wife screaming in the front row anyway ?