I’ll try to reformulate my goal, but as it doesn’t seem to be any obvious solution that I have missed, I am grateful for everybody’s efforts: it seems like @TonH’s solution (and @Vadian !) is the best (I tried it this morning), as I thus end up with a layout targeted for my needs, even if it might imply a re-import of previously created materials into a new project created with this “Piano in H” template. I am not sure if it is actually faster than having a checklist handy, with the options I want and running through them whenever I need such a layout.
I expected there to be something like the templates of the engrave mode: For this layout, I want to apply such-and-such options (like I stated in my first post). The most important ones for my application are “Clef and transposition overrides” from the triple dot of the layout in setup mode (which needs to be c=cb for all c instruments, and c=a for Bb instruments, etc), and “Transposing layout” from Layout options proper. I also generally don’t need staff labels after the first line. Even if that is my default for “proper music”, I’d rather use that space (and truncated vertical spacing) for a bigger staff size. In short, there are a few layout-related properties I was hoping to change in one fell swoop by applying some kind of template, a subset of settings via a .doricolib file or something. Currently, it seems like I have to store a layout in a “real template”, and then import the musical materials into this, if they have been created in advance. This works, even if it feels like putting the cart before the horse.
So, a couple of use cases:
In real life, things are usually as they are. I find myself accompanying for rehearsal on a piano which, for some reason or another, sounds around a half note too low.
So, in comes a violin player with a piece in G. The accompaniment score (kind of a piano reduction of the orchestra) for “Imperial march” is more than I can transpose live and play in Ab at the same time as I encourage him, and help him find his own voice, counting ledger lines and keeping track of what position on what string he is playing. Previously, I have had a few attempts at creating an accompaniment sheet with an instrument “Piano in H”, but this of course leads to me having a grand staff in Ab, and then the violin part in G, which doesn’t help me much as I now have to switch my thinking everytime I need to give him a little support. So, instead of also creating a “Violin in H”, I search the web and find a pointer towards the “Clef and transposition override” setting, which in an instant solves all my problems.
It is also a more elegant solution when I only have a lead sheet style score. The cornet girl presents her practice piece. Now, with a few jazzy chords, the notes are written in C (sounding in Bb, of course), and the chords are — considerate enough — written for a piano. This means I have to support her playing transposing the notes to Bb at the same time that I remember that this Cmaj7 is to be played Hmaj7 to sound correct. In this case, I don’t really need the “Piano in H” instrument at all, as I am really only interested in the melody and chords, not having to create a “Cornet in A” — well, that actually exists, but the point is still valid.
Increasingly, I scan the notes (with the camera on my phone), convert them to MIDI, import them into Dorico, and make a few tweaks before creating a new layout that transposes everything correctly. Now, it would have been wonderful to create a layout in this score and apply a template with the necessary settings.
I’ll make it work anyway, and I thank you all for your suggestions. I hope it is clearer why I raised the question. It seems the best way to speed things up might be to reframe the problem so the layout settings are applied first (via the template), not last (as per my presented workflow).
Thanks again.