From here on it was easy: the retrieval of the adapter was a cinch of course, and yes, one of the 2 set screws was not tightened. after a quick inspection, no other problems noted, I reset the adapter and tightened both of the 2 (two) set screws. Successfully. That thing is stable now. Re-assembly is quick and simple, the only tricky part is the proper adjustment of the locking ring, it became finger tight about 180 degrees before "home" and again, using a small hammer and a screw driver I tapped it until my mark and that hole in the ring matched up. A quick check "how does it feel" to swing the mount about the RA axis? not stiff, and not loose, and no free radial play. According to Ioptron that's what you want. I pulled the cables through "their" windows in the adapter, and made sure I did not create a wire-braid behind the window.
Then I connected the mount and let it find "zero position" before inserting and setting the polar scope, to make sure reticle 12 o'clock is really @12.
The subsequent polar scope alignment with RA axis went according to the instruction posted above, and it is best done at this point, with the PCB/ cover plate out of the way.
Reconnecting and putting the "electronic sandwich" back requires that one pushes the cables/ wires back into the space behind the adapter, I used the hemostat clamps to do this carefully. Nonetheless, specifically the shrink tube around the USB cable looked beat up despite all my efforts, so I checked that before closing up.
Reattaching the reticle-LED: don't forget/ loose that mini spacer.
Before setting the little bubble level, again let the mount find zero.
Thats all, folks.