You chose a tedious job.
It is a pity that we really do not have circuit diagrams of the TA Triumph Adler / sks of the Px machines of the plug-in cards.
I still have a sks-KISS CPU card - which I successfully tested in a P2U. But I had to change the MOS part (KEybord) EPROM to start in TA P2 and work with it.
A friend had made a HARDPATCH on this KISS CPU around 1981. Use a switch (normal - no BANKING) and SPECIAL as banking via PORT 78h (as with TA P2 / P3).
Clearly, unfortunately, no sketches - but there are a number of IC piggyback and various thread wire connections.
I hope to forograph the map soon and to identify the lines.
Possibly. you can create a great base with or other USER.
So good luck and see you soon.