RealDMG

For what its worth, I use the 4CM with the Helix and an Orange TH30. I like the clean and dirty channels on the TH30, so I mainly use the Helix for routing and effects but lately I've been getting a little creative with the Helix preamps straight into the power amp section of the TH30. I just bypass the Orange head through the routing and it works fantastic. I get the tone of the TH30 when I want it and still have the ability to play with some different preamp tones for certain parts of songs.

I've heard of some folks having luck with a standard acoustic guitar amp, like an Acoustic A40 or A100 as a monitor but I wouldn't know if that colors the tone at all. The wedge shape makes for a good monitor, though.

I also run a Helix into a TH30 using the 4CM. I couldn't find any data to support this, but I'm pretty sure the effects loop can be run instrument level. I'm running everything instrument level with my rig and have zero problems or noticeable volume issues.