This snippet shows how to associate drum-notenames with custom stencils which will automagically be used as the standard notehead for the assigned drumnote.
In your ly-code you need to have these stencils defined. A simple example can be found in this snippet. Additionally there are two more examples used in this snippet for demonstration.
The second step is to customise the list (stencil-mapping) where the drumnotes are assigned to new stencils.
List only those drumnotes you want to have displayed with your own notehead and be sure to put the full notename, not its abbreviation, e.g.
'bassdrum will work,
Off course this will also work with custom drumstyle-Tables and, if used, with custom drum-notenames.