Can't change noteheads in 4.5.2 on a Mac using Musesounds Marching Instruments

Hi all,

I feel I've exhausted all options, and I still can not create a custom note head on any marching percussion instrument using the Musesounds Snare, Tenors and Bass Drums on 4.5.2 on a 2024 MacBook Pro. Select note > Palettes > Noteheads > any selection...nothing responds. I've tried adding a completely new note in Customize Kit, but then I can't get any sound out of it.

All I'm trying to do is use the Half Note note head for cross-overs in my Tenor parts. Super stock stuff. Can't do it.

Any help is appreciated.