Monitor has to be powered also.

I could use one of my CM-30s on those few times I am in that situation, although it is one more piece of gear.

One more piece of gear... another audio cable... and another power cable to plug into the power strip. Also add 1 minute to your setup and tear down. Would you need the mount the CM30 closer to ear level? Then you need a mic stand or a table.

It's best for you to hear so you can give the best performance.

I agree. It bothers me no end to not hear accurately, especially, when I hear very well. I have a wealth of options from my friends at Synthzone, and in case I am backed up against the wall again, I will handle it.