My Symphony includes three flute parts: flute 1, flute 2 doubling alto flute and flute 3 doubling piccolo. I want the 3rd flute under the second flute in the score, but when playing piccolo, I want the piccolo at the top. This is the way it is in scores from Boosey, and I think it should be like that.
How can I make Dorico not decide itself what is flute 1, 2 en 3, so no “automatic numbering” and put the piccolo where it belongs and flute 3 where it belongs in the score?
This has been discussed (at length).
I believe the consensus solution was to use separate players for each flute, piccolo and alto flute (so your score order is correct), and simply combine Flute2/Alto Flute and Flute3/Piccolo in Part Layouts (removing the default layouts for those instruments). In the part layouts, hide empty staves.
Okay thanks. Sorry, I couldn’t find it.
Note that this method obviously can’t flag instrument changes automatically, so you’ll have to add those by hand, using Staff Text in the appropriate paragraph style.
Also, you may have to babysit your system breaks both in the score and the parts if there are changes quick enough to potentially fall within a single system, as the extra staff would break the illusion.
good to know, and to reserve time for this. And hope they read this and solve the problem. Thanks!
What problem? You can show/hide staff labels at any system break.
The problem that it’s more work, as @hrnbouma pointed out.
But relative to what alternative?
To make the flute and piccolo, or flute and alto flute into one player and adjust the order in the score, and make players into 1, 2, 3 without having to do a workaround to make Dorico do it. I’m pretty sure they will implement that soon… they’re best! 
You’re very optimistic…