Remove duplicate notes across octaves?

I’m doing a reduction from a fairly large ensemble to a smaller ensemble. I’ve been using the reduce/explode functionality with much success… but I have a huge passage coming up where there are a ton of duplicate notes across the octaves and I don’t really care which note is selected, I only care about one pitch class, from which I will determine the appropriate voicing. You can see in the picture here, I’ve manually done the first three half beats (with much hair pulling!) by going in and moving the notes around and deleting any that come up as duplicates… but this is pretty laborious. If I could just paste w/o duplicates it would probably save me several hours of work with this project. Any ideas?

You could select both flagged chords and delete them (they are the octave to the two lowest notes). Then select either manually or by filtering the top notes and deleting them (as they are also octaves).
Then it depends on the instruments you use in your smaller ensemble, how to distribute the notes.

are they different voices? (View menu > Note and rest colors > Voice colors). Select all for that section, filter, voice… )?

This ^^
Please: turn voice colours on and make signposts visible
They really are a great help to understand what’s going on in your file and you will easily be able to cure most of the strange (unexpected) things that happen.
This advice works for beginners as well as powerusers (but those usually use them as soon as they’re needed)

That looks like it identifies some of the duplicates (though I can’t necessarily guarantee that). What I’m doing is copying from the score that has 7 parts and reducing it to 3, so I have to make the decision to keep say, color tones rather than the fifth, for example.

I’m looking at the mapping functionality and thinking that I can just map every note to a specific octave, and then it would at least already be visually the same note and easier to delete.

(note this is a different measure than I first posted because I’ve done a little bit by hand since last night).

I’d say right idea, wrong octave (at least for my thinking). I’d have moved everything down an octave where I would not only see the overlap but also could identify the pitches without counting ledger lines.

Hope that helps.