Battery Percussion notation: Custom note heads?
A little background.
I've been using Musescore for a while as a volunteer percussion captain head for a local high school with limited funds. Musescore is what the band director uses, funds for Sibelius are out of the question. I use Musescore for both battery/keys part writing and digital audio recordings for the kids to listen to. I have spent a good deal of time developing my own sound fonts to get the best sound quality I can.
So two obvious and exhaustively discussed problems are Flams and Buzzes. I have audio work arounds for both, and print work arounds. But this causes me to have to develop two charts for every arrangement (one for audio, one for print.
For those that don't know, the way grace notes are implemented in Musescore is geared to a wind instrument and does not at all translate to a the same grace note sound in terms of velocity (volume) nor rhythmic spacing for a proper drum flam. And there is no 'Z' tremolo option for Buzz notation.
My work around for Flams was to develop a single Flam sound, insert it into the sound font and assigned it to the slash note head in my 'Battery Drumset'. There is already a single sound for a buzz, but it's notation is the trapezoid note head instead of 'Z' on the stem. The print work around is to use 'staff text' and literally align the letter 'Z' to the stem.
So on to my question.
Is there a way to add a custom image for a note head? I would like to have a notehead that has both the single dot and a smaller grace note next to it, and a note head with a Z slightly above and offset. I can create the images with no issues, I just have no clue how to insert them into the Symbols and make them available for use.
Images of note types in question attached.