derp. The topic title was supposed to be: ~ vs −

In linguistics it might not be a good idea, but since you say display font, it's probably not going to come up. A straight line is fine in Spanish but other languages that distinguish tilde vs acute might. In this font, how are you doing your macron vs your acute?

«El futuro es una línea tan fina que apenas nos damos cuenta de pintarla nosotros mismos». (La Luz Oscura, por Javier Guerrero)

"In this font, how are you doing your macron vs your acute?"

They're identical.

"other languages that distinguish tilde vs acute might"

I don't think there are any. I suspect no languages include both macrons and tildes but I'm, not sure.

So how are you doing your acute vs your grave?

So if your macron, tilde, and acute are the same.... is the grave the same as well?

Portuguese distinguishes á à and ã.

«El futuro es una línea tan fina que apenas nos damos cuenta de pintarla nosotros mismos». (La Luz Oscura, por Javier Guerrero)

You might have to include a disclaimer with the font:
"Not suitable for Portuguese"
But you'd probably have to write that in Portuguese.

Portuguese is just the only one that came to mind. I'm sure there are others. Probably a lot of Native American and African languages, and some native South American ones as well.

«El futuro es una línea tan fina que apenas nos damos cuenta de pintarla nosotros mismos». (La Luz Oscura, por Javier Guerrero)

Sorry about that. I completely botched the answer. Yes, my acute and grave look like a proper acute and grave. Only the macron and tilde are identical.

As for other languages, so far, I haven't come across one that includes both tildes and macrons. The exception being descriptions of long vowels, dictionaries etc. Nothing where you'd likely a display font.

You could probably still disambiguate the tilde from the macron by attaching small rungs of sorts on the edge of the macron design. Just putting a bottom rung on the left side, and a top one on the right. You won't have to curve it, and will be using a more traditional style to boot.

«El futuro es una línea tan fina que apenas nos damos cuenta de pintarla nosotros mismos». (La Luz Oscura, por Javier Guerrero)