I have trouble creating the following sort of beam that is centered over a rest (see the picture). Maybe I’m missing something really obvious, but I seem unable to figure it out. Thanks for any help.
This should be very simple: you can input all the notes for that beam on the lower staff, then select the top F and press N. Full steps also described here
When both notes of the first F octave are on a certain staff, either above or below, it works perfectly as per the instructions you describe and creates the center beam. But having only the top F note on the above stave breaks and refuses to center the beam for me for some reason. Force centered beam in edit → stem doesn’t help. I’ll try looking at the options some more… thank you 
Welcome to the forum, tpajoj. I’m afraid Dorico doesn’t support centering a beam when there’s a rest in the middle of the beam group.
Hi,
I have exactly the same problem as tpaloj, fiddling around for two hours trying to find a solution until I found this thread and this doesn’t seem to have been fixed in Dorico 3.5. Could we please have the option to center beams between staves in a grand staff even when there are rests in between the notes. That would be very helpful.
Si può fare benissimo! Eccovi gli allegati:
Prova.dorico (387.2 KB)
Bisogna impostare questo e poi ricorrere ad un escamotage:
…ed ecco il risultato:
Buona Musica.
Salve,
sopra ho allegato il file Prova.dorico per dimostrare che si può fare però sarebbe bene che nella prossima versione di Dorico questa procedura fosse più facile. Speriamo.
Buona Musica.