The answer is... I don't know :-) Maybe both? What do you think would be best?

Done! Thanks :-)

Thanks! I'm chuffed with how they turned out.

Nah, that's just me not adjusting the positioning of the apostrophe. Lots of clean-up to do :-)

Oh! That is very clever. Thank you.

Both! Unicode has some support for as-is ligatures. For example fi is U+FB01.

Modern fonts can also use self-defined ligatures. That's how fonts like https://www.sansbullshitsans.com/

So my plan is (eventually) to add in ligatures where Unicode has defined them - and automatically replace typed text with self-defined ligatures where it doesn't.

Cheers. The code was cobbled together by me from various random tutorials and things I had laying around.

Cheers! I'm hoping to add some more letters and tidy up the rest when I have more time.

Thanks :-) It was a couple of days work. Mostly teaching myself stuff that I'd forgotten. I blogged about it so others can follow the process if they want.