Lionel,To write rhythm section kicks above the chord symbols:
1. Add an extra staff above the lead sheet staff. This extra staff is for the rhythm section kicks only. So the big work is about hiding this staff everywhere else:
In the Staff Attributes dialog box go to the Staff pop up menu, and select "0-line with Full Barline".
In the Items to Display pane, deselect everything.
Also deselect "Display Rests in Empty Measures".
You might also like to try the alternate notation called Rhythmic Notation:
Click the button "Select..." (there are 4 buttons called "Select..." - I mean the button for Alternate Notation). In the Alternate Notation dialog box click "Rhythmic Notation". You might also like to select the option "Stems Up In Rhythmic Notation". Click OK twice to return to the score.
Rhythmic Notation will give you special noteheads, all on the middle staff line, no matter what pitch you enter.
2. To get rid of the left barline, switch to Measure Tool. Select all measures, and double-click a measure. Set Left barline to "Invisible". Click OK.
To get rid of the measure numbers above the extra staff:
Measure menu > Measure Numbers > Edit Regions...
Deselect "Always Show on Top Staff". You might also like to edit the Position of the measure numbers. Click OK.
3. Enter the rhythm section rhythms in the extra staff. You can use the Staff Tool to adjust the vertical position of the staff.
4. When each system contains the number of measures you want, lock the systems, update the layout, and you are ready to optimize staff systems using the Page Layout Tool. Optimizing will remove the extra staff in all the systems with only empty measures in the extra staff. It is important that you don't optimize until you have entered all the rhythms. Rhythms entered after optimizing might only be visible in Scroll View, not in Page View. To make them visible in Page View, remove optimizaution, and optimize again.
Peter