(if this is better suited for COFF, that'd be fine too)
I've been trying to set up UUCP on my V7 system and its raspberry Pi host. This plus the "s" editor (already working) are really all that's needed to make this something pretty close to a daily driver, if all I wanted to do was write text files (which in some sense is all my job _is_, but to be fair I get a much more immediate feedback loop in my current environment).
I have 16 DZ lines, I've set them to 8-bit mode. They're working fine, because I can use them for terminal sessions.
As a long time UUCP person on PDP-11's, "Danger Will Robinson."
Just for grins and giggles on the V7/PDP-11 side, try it over a DH (VH driver in simh) emulation (or even a KL/DL - although the simulated interrupts will be a mother). That said, the VH driver is a not exactly a DH as I understand it, its the later QBUS version which was similar but different. It's been on my list of things I want to chase down at some point to make work to get it closer to the original.
FYI: Running UUCP over real DZ's was always troublesome. There were a ton of updates/patches done post the original V7 release in the DZ drivers to make them play better. Most of us that ran large UUCP set up in the old days, installed ABLE DMAX (DH/DM) that were a single board DH replacement - they are DMA, and buffered (and supported proper modem control which the DZ's don't - although later UCB work on the driver sort of faked it enough to make to it work for basic dial-up use reasonably reliably).