Use (regular) Upstem Voice 1 with Slash noteheads for the stemmed slashes (you can set this up to work automatically from the Edit Percussion Kit dialog), and you’ll find that no extraneous rests are created.
Use (regular) Upstem Voice 1 with Slash noteheads for the stemmed slashes (you can set this up to work automatically from the Edit Percussion Kit dialog), and you’ll find that no extraneous rests are created.