Received a response from ZWO via the FB AM5 group that the ASCOM driver currently does not have a mount limits function, but stops tracking at the meridian. Whether this will be sufficient for me remans to be tested.
I have now had a chance to try out the AM5 on the second pier with the ADM side by side saddle, which will be the main mode of operation. The results were most satisfying, tracking about .8", even though PA is still about 10" due to other holiday activities intruding, with the HTM 150, NUC and ZS61 guider all installed, no balance done and no counter weight (yet). I plan on throwing on a ~2Kg, after I've completed mount interference checks. Operational pics to come.
I came across a good YT comparison of Harmonic vs EQ6 mounts, well worth a look.
https://tinyl.io/7c3n
Must admit, so far I'd recommend the AM5 for a medium-duty pier. I'll get some photos of the side by side setup, probably with the RC8, NUC and ZS61. Cabling is far simplified from the EQ6.