I am so giddy with delight at finally having capo chord support in Dorico! It’s reliable and very well implemented… but I do think the actual setup of capos is a little burdensome. Might I suggest:
Add capo setup to the Shift-Q popup. Typing “capo 3,” for example, could add a standard m3 transposition capo line to all chords in a flow; perhaps “(capo 3)” could create a capo/alternate chord in that specific location only.
Add capo controls to the Lower Zone (getting used to that nomenclature!). Set the fret or interval, establish a range for capos (single location, bars, flow, all).
For those who think in capos, add parentheses as a function in the popover, so that (D) would add an F chord. OR: use brackets instead, and allow (D) to create a parenthesized main chord!
Auto-create capo instructions, with Engraving Options for “Capo at fret x,” “Capo x,” italicizing, and so on.
All that said, I think your implementation is already superior to anyone else out there and I genuinely appreciate the add!