I have recently switched from Sibelius to Dorico and although there is quite some way to go for me (I was using Sibelius for more than 10 years) I am really excited about Dorico.
Currently I am working on a transcription for guitar of some song where there are some overdubs so the actual one guitar is playing some additional licks ocassionally throughout the song.
There are always some alternate ways to notate this (e.g. adding another player and hide the empty staves which would be perfect if it was a second musician), but since it is only the same musician these kind of additional phrases are notated in commercial transcriptions on the bottom of a page in a seperate staff often boxed and marked as „fill n“ and at the very bar there is a text indicator where it is referred to it.
Since I am new I think I still did not cover all what can be done with flows but as far as I understand the concept, flows are linear so if I would notate it as an additional flow such a fill will only be played back after the ending of the previous flow (and thus not at the same time which it should).
Thanks for your help!