After my impasse I just hopped around a bit and worked on remaining entries. All my new entries are supported by triplets in the clues, but I confess the object eludes me as I just get nonsense even allowing for some ambiguities. To be picked up tomorrow.
I rather share the feelings of those finding the endgame tedious, though, to be fair, there aren't too many options at each change, and in some cases, such as 13d, there is only one possible altered entry.