I think John Barron may have addressed this in one of his videos several years ago, but I couldn’t find it in the forum. So I worked out a procedure that works acceptably with Dorico 4, to whom it may concern.
Often jazz band charts are simple enough that the drummer needs little more than a “road map”, with few or no actual notes written to be played literally. A common style for this kind of chart may look like
Here is a procedure to achieve that result:
1. Create a playing technique (see below)and save it in the “Unpitched percussion” category. Notice I selected “Chord symbols font”, which was a suitable size and style for my needs. Notice also that I added the wide wiggle line, which is a common look for this style of notation.
You will need to create a separate PT for each combination you will use, e.g. “Play 16 bars swing”, “Play 6 bars bossa”, etc. You will probably want to save each of these as default so that they will be available in other projects.
In the drumset part (or in the score with global propagation on), lay out the systems in their final configuration, with default whole rests in all the measures where you will be adding one of these playing techniques. Typically this type of notation will have 12 or 16 bars in a single system. If the song form is repetitive, use the casting off value in the drumset layout to automatically set that many measures per system.
For each system where you will add these PTs, select all the measures (rests) in that system. Rests are a real problem. You can’t hide them through any straightforward means without unhappy consequences. If you try to eliminate them, the bar lines will lose their proportion. If you try to color them white, there is residue that messes up the staff lines. However, you CAN set them to transparent. You do this by displaying the properties while the rests are selected. Activate the color property. Click on the color selector, but leave the color black. Instead, change the number in the alpha channel from 255 to 0. That makes the rests transparent when printing, but you can still select them in WRITE mode if needed. Please note that when you “print” from Dorico, you must select COLOR. The alpha channel is not respected in B&W printing.
Finally insert the PT while the range of rests is still selected. That should extend the squiggly line to the end of the system. With the PT still selected, in Engrave mode, set the Y offset to minus 4-1/4 and activate Erase Background. That will place the PT in the center of the staff.
Repeat this process for each of he sections that need such a PT. If they are all the same number of measures, you can simply copy and paste the PT, which just takes a few seconds even with a long chart.
One caveat: You can and should use rhythmic cues liberally so the drummer will know where important punches lie. However, that seems to throw off the Y offset of the PT. So you may have to adjust the Y offsets. Too bat there is not a placement option of “Center”.