2-bar drum cue

I am writing a simple arrangement of Holst MARS for electric bass. I want to give the bass player a two-measure cue of what the snare drum will play (see attached - two empty bars preceding entry on low F).

Two questions:

1) How do I insert x's for the rhythmic pattern in those two measures; and,
2) What is the best way to show tiny measure numbers above the repeats to help "count" the number of repeated measures (since this ostinato pattern can be "a tad" boring).

I'm on a Mac with MuseScore 3.4.2.25137

Pete