This is pretty nice: thanks for including polytonic Greek and macrons over Latin vowels including over y. I especially love how the breathing marks and accents look together over initial vowels in Greek, and I love zeta (ζ) and xi (ξ) in this font.

Might I make a few specific suggestions:

- allow combining breve over Latin y as well: sometimes that's handy for indicating contrast

- check the height of stacking diacritical marks: a perispomenos tonos or circumflex accent over a breathing mark over a vowel (like in εἶναι eĩnai) ends up stacking up tall enough to intersect with descenders (like on ζ zeta) from the line above

- the circumflex over alpha (ᾶ) looks really good, because it follows the curve of the alpha itself, but circumflex over eta (ῆ) looks off-center, because it left-aligns to the ear on the left of eta. The same could be said for the iota subscript (ᾳῃῳ): it looks great under alpha and omega, but it's a bit awkward under eta because of how far to the left it is.

- have you considered adding a variation for the Porsonic or single-curve circumflex?