dpapavas

I know what you mean. I solved the issue with a specially designed adjustable linkage on the Lagrange (https://github.com/dpapavas/lagrange-keyboard). It took a while to finetune the relative position anf attitude (which, turned out to be what one'd expect: 0° toe, separation at about shoulder width), but now it's finally consistently aligned every time. (The palm keys also help by doubling as guides to keep your hands in the right place.)

Yes, it doesn't display correctly on smaller displays. I'll have to look into that.

Assuming by "playing against it" you mean actually playing the correct note on a guitar and having the application directly verify it via sound, I've considered it, but I have doubts it would be practical. Besides the need to actually have your guitar near a suitable microphone in a noise-free environment, you'd need some sort of functionality like in a typical tuner application, but given the tendency of such applications to jump frequently between the actually sounding note and others (harmonically related I assume), I'd expect a lot of false negatives (or even positives when you get lucky). Still, it might be workable and you can't tell before you try it, so I might give it a shot in the future.

As far as I can tell though, the basic advantages of using a guitar, would be that you actually train your muscle memory, by having to fret the note with the correct finger, instead of just visually identifying the correct fret and that you'd get audible feedback in the form of the note actually sounding. The former is, to some extent, possible with the application as it is. I've implemented various modes, but the only one I use any more, is the randomly picked position, which enables certain keybindings, which allow you to turn your keyboard around and hold it like a guitar (I have a split keyboard so I only have to hold up half of it; not sure how practical it is on a normal keyboard). You can then "fret" the keys with the correct finger, which should hopefully build muscle memory as well.

I haven't implemented sound yet, but I'm considering it, so, once that's in place, your suggested functionality would amount to implementing a timeout for each note. Feel free to open an issue request on GitHub.

Isn't it already touch-friendly? You can select the correct fret by tapping it. If it doesn't work for you, try opening an issue on GitHub[1].

(I did notice though, that on my tablet the notes aren't positioned correctly, so I'll need to look into that).

[1] https://github.com/dpapavas/fretboard-trainer/issues