How to add rehearsal marks with measure numbers instead of letters

1. Select the first note where you want to have a rehearsal mark
2. Drag a Rehearsal Mark from the Text palette
3. Change the letter A to the appropriate measure number
4. Select the first note where you want your next rehearsal mark
5. Add another rehearsal mark from the Text palette—it will automatically adapt to the measure number

Note that if you insert a new measure between two rehearsal marks, the numbers will not change automatically. Run Edit → Tools → Resequence Rehearsal Marks to readjust the numbers.