Anybody try hooking this up with 2 amps via the fx send L&R?
The big question- is it slicing the levels? If it can do this with little degradation, I may rethink my FS post....

well, I only have 1 amp at the moment (Mesa) and was jammin the 4cm
There was a hint of signal coming through when I turned on a patch that did NOT have the loop engaged- this should have just been the 11R's amp tone (which was a clean Fender), but instead I heard some Mesa hi gain preamp fizz deep underneath in the signal. I unplugged the cable going from the 11R fx send>Mesa input; meaning it was just the 11R>fx return and the problem was gone. I looked at the settings a bunch, but I wonder if there is seepage? It was buried pretty quiet, but it was there.
Still doesn't answer my amp splitter question, but I'm thinking it may be fine for that. The signal was a bit livelier without the 11R, but it was close

Found the seepage
The Recto's presence control is engaged through the fx return, but only if there is something in the input during 4cm