two note tremolo how? manual doesn't say

How can I get this to work?
I wanna turn what’s on the lower staff into a tremolo. I figured it out for the first 3 beats. But the rest of the first bar looks weird.
I got to what’s on the upper staff by inputting two eighths and tapping “three-strokes multi-note tremolo”. But now it looks like two tremoloed quarters when it should be two tremoloed eighths…
Moreover, I’ve gotta tremolo across the barline, which I don’t know how to do.
Manual has very little on this and nothing useful that I could find.
Multi-note tremolo across barline.png

The relevant bits in the manual for inputting tremolos are the steps for doing so with the popover or with the panel, and the reference doc for the popover that has examples of what you can enter into the popover to achieve different things (3rd table is for tremolos).

Tremolos across a barline: should be as simple as selecting 2 notes that cross a barline and inputting a multi-note tremolo. (E.g. in your example, you could turn the first F, assuming treble clef, in the group of 4 16ths into a quarter note, do the same at the start of the next bar but change the pitch down to a D, select those two and input a multi-note tremolo.) However, if you do want to do this for the lower staff in your example, where there would be 1 beat of tremolo on the left of the barline and 2 beats on the right, it’s probably notationally clearest to have separate tremolos either side.

Two eighths becoming quarter notes in a tremolo: this is automatic due to the notation convention of both notes displaying the overall duration of the tremolo (e.g. as described in ‘Behind Bars’ by Elaine Gould). Each tremolo stroke is the equivalent of a beam line, so you should select/input the appropriate number of tremolo strokes for the number of notes you want to hear within the tremolo (apologies if you already know this). There is also a threshold in Dorico for how many tremolo strokes is considered “unmeasured” and therefore played just “as many notes as fast as you can”.

Thanks! Big help. Much appreciated!

Further question with your last paragraph. Even if I reduce the number of strokes between those two 8ths, the two notes remain (looking like) quarter notes. Am I missing something?
I guess I must have forgotten how multi-note tremolos are supposed to look.

This is what I got. Is this correct?

That’s how it should look, yes. Each of the two notes in the pair is notated with the total duration of the tremolo.

Regardless of the number of beams connecting the notes of a tremolo, the connected note values stay constant, quarters in your case.

[Daniel responded while I was making the image :neutral_face: ]