hello,
i’m a composer and try to design some special stem with symbols, for example, this one:
I actually created a new notehead, I don’t know how to create a new stem directly, so I use this way.
I added a bridge symbol in the stem. I found that the lines which I circled are longer. It looks not good. How could I solve this? actually, if the bridge symbol is bigger, then the line would more longer.
I really want to make many different stems with different shapes, for example, circle, triangle, arrows and so on , so I need to solve this question.
Thanks for the answer.
Florian
Welcome to the forum, Florian. Dorico doesn’t currently have a good way to produce your own generalised stem decorations, though this is something we intend to add in the future. For the time being, provided you don’t need too many of these in the same project, your best bet would be to repurpose one of the tremolo strokes in Engrave > Music Symbols, as these will automatically be centred on the stem and won’t affect ledger lines.
I am in need of the same issue and am for now using the notehead solution, as I need different tremolos in this piece as well.
On a related note: I found Penderecki and wieniawski unmeasured tremolos in the SMuFL list, which I love!
Sadly, there is no actual unmeasured tremolos in the repeat section.
For now, I replaced the buzz roll, but I can see myself using both in an orchestral score.
I really would also favor additions in this direction, as a lot of other things are already amazing for us contemporaries 
