Stacking diacritics for Ancient Greek

Unicode encodes accented letters for Ancient Greek in the block “Greek Extended” starting at U+1F00. The block includes 12 precomposed characters (ᾰᾱᾸᾹῐῑῘῙῠῡῨῩ) with a superscript breve or macron to denote short vs. long vowel phonemes. My issue is that combinations of these with other diacritics (oxia, varia, psili, dasia, and dialytika, alone or in combination) are not supported by “Gentium Plus”, but they do occur in my preferred Ancient Greek dictionary (and in other more “detailed” works) where the length markers are put just below the other diacritics, thus: στᾰ́δῐον, δημοκρᾰτῐ́ᾱ, Κῡ́μη etc. Are there plans to add support for these stacking diacritics?

That has been on our list for a future version for a long time, but we haven’t had the capacity to work on it. Thanks for the request - it helps us to know that someone would find it useful, which pushes it up in priority.