Okay, just for fun I just exported ALL the Universal Horns on one poor Gen 8 guy, and brought it in via Transformer.

A couple of notes:
1) Some (one?) of the horns will hide certain parts of the Gen 8 figure, causing an error in Transformer as it can't find a suitable mesh. Just use the "drag over another Gen 8 figure" into the scene trick before you export.
2) There are some very useful morphs on each horn you can also import into CC3. Just use the import morph rule with "UH" as your beginning and you'll get them all.
3) And, as I said, make sure you bring them in as accessories (which they are -- they are NOT clothing, as Transformer will incorrectly identify them as).
Other than that you should be good to go.
Alienware Aurora R16, Win 11, i9-149000KF, 3.20GHz CPU, 64GB RAM, RTX 4090 (24GB), Samsung 870 Pro 8TB, Gen3 MVNe M-2 SSD, 4TBx2, 39" Alienware Widescreen Monitor
Mike "ex-genius" Kelley