Question two is answered. It's super easy to setup and build routing. In this case I was running the QC's XLR outs to a pair of FR12s.
I connected instrument cables (4) from QC send/return 1&2 to VP4's in/out. On the QC grid I first set the beginning of row one to input 1, the end of row one to Send 1/2, the beginning of row three to Return 1/2, and the end of row three to multi out. I set the VP4 to stereo input mode. That setup worked fine.
Figuring there was probably a more efficient routing method, I set row one to go straight from input 1 to multi out, and put an FX loop block in the middle. That also works perfectly fine as far as I can tell.
Additional bonus: the FX Loop block has a send level and a thru level. I set the VP4 up with a reverb and cranked the mix up to 100%. I turned the thru level on the QC's FX Loop block all the way down and as expected the reverb came out 100% wet. I turned the thru back up and reintroduced the dry signal. This is nice because it's an easy way to get all of the VP4's effects in parallel to the dry signal if desired. I imagine it should be pretty easy to get a W/D/W setup going.
Also, even though it's not 4CM it maintains some level of that versatility. It would be easy to use the VP4 for pre-effects in one preset, using the QC's delays and reverbs; or use the QC's pre effects and the VP4 for post effects. That's kinda cool and better than the fixed way I had the VP4 setup with my real amps. Seems pretty slick.
On the very slightly negative side is that one of my reasons for getting the QC was its small form factor. The QC with the VP4 next to it is about an inch wider than the FM9 so it somewhat reduces the form factor benefit with just the QC. On the flip side I don't need to add a drop pedal like I did with the FM9 (I like being able to use virtual capo and dual detune at the same time) so it still seems significantly less bulky than the FM9 pedalboard I had (which wasn't built to be small tbf so it's definitely an unfair comparison).
That's it for now. Might mess with this some more soon. I was just testing as proof of concept so I didn't even start adding amps or anything yet. That'll be next.
2 spdif cables from front to backline 
