Trills of common duration, like a measure or so, are easy. Just add the trill and stretch the squiggly line how far you need.
What I'm currently working on has passages with very short trills. What's the best, cleanest, most acceptable way to notate what I have here?
The time is 2/4, key of F. Piccolo is doing little bursts of these short trills. In the first measure, I've just used a Mordent to indicate the short trill. The second measure is more accurate, showing exactly what I mean, and the duration is precise. But - is that too much to indicate? Is there another method I haven't shown here?
I'm not concerned about the file playing back exactly right in Sibelius, I want the printed score to be correct.