I spent the weekend mounting everything and getting it all to fire up and everything talking etc...all seems to work
So I now have two completely separate imaging, guiding and focus systems that I can swap between in a minute, one wide field one narrow field
Although it took a bit of counterweight

(that's 47kg on the dec shaft end!) some improvisation (big washers, aerobic ankle weights and pieces of gal steel channel), plenty of gaffa tape aaaand lots of hair raising moments holding a heavily imbalanced rig while changing counterweights etc, by my self!

...balance is perfect all over the sky, movement is smooth and high speed slews seem no effort and no slippage detectable.
Waiting for next clear night to confirm I have the MegaMOAG setup right and to inspect the field tilt etc...
Happy days
Gunna have to be very careful moving around it all in the dark though, the whole rig is much wider now with sticky outy bits everywhere! will be a bit more ducking and weaving going on inside the dome