Thanks for the offer, Ben. But I need to learn this for myself, although I will certainly bombard you with questions!
You can change how & when notes are shown as tie chains or dotted notes on a per-flow basis in Library > Notation Options > Note Grouping.
Take note that some options are for when potential dotted notes are followed by notes, vs followed by rests. Eg if you input a dotted quarter at the start of a 4/4 bar, it’ll appear as a quarter tied to an eighth - but when you then input the (big assumption, admittedly) next intended eighth note, you’ll probably notice it gets updated into a dotted quarter note.
There’s no “one-stop shop” like JW Staff Polyphony in Dorico, but judicious use of filtering, copying and pasting should allow you to separate material for individual voices on one staff out to multiple staves as needed. For example, filter all the notes in the up-stem voice, copy them to the clipboard, and paste to another staff; for the down-stem voice, consider using “paste into voice” to paste into the up-stem voice (otherwise, it will be pasted into the down-stem voice, which might not be what you want).
Lillie has provided some hints on how to get the notated values you want, but you can force Dorico to do exactly what you tell it by activating Force Duration (shortcut O). In general I wouldn’t recommend this, but if the majority of your work is reproducing existing pages of music, and it’s unlikely that you will need to make significant edits to the musical content, working with Force Duration activated may save you some time.
It’s totally OK for you to like Finale better. If nothing else, you’ve been working productively and presumably reasonably happily in it for many years. I hope that as you get more familiar with Dorico you will start to see some benefits.
Mike, another thing to realize is that Dorico’s standard notehead size (at least in Bravura) uses slightly oversized noteheads in place of the noteheads labeled Default. It might be possible that if you switched notehead sets to the Default size, you would find the size more familiar (although I do not know whether this applies to Finale SMuFL fonts or just to Bravura).
By putting choral music into the iPad version of Dorico, I’ve found that singers not only can play an individual track, but they can also tap on individual notes to hear them. Of course this only works if they have an iPad and Dorico, and know a little how to use it. Still it’s pretty cool to tap on a note in your score to hear it.
It is possible to assign each Voice (read: Layer) in Dorico to a separate mixer track, so you might not even need to split them out to different staves.