Well, i have tried placing ores manually after changing harvest level in config (first i thought that this depends whether they are generated or placed manually, but some work correctly, and some still have default harvest level, i'll test more for what ores do that).
EDIT: Ok, i have tested every ore, there are quite a few bugged ones:
1. Ore is in config but not present ingame (Lemurite, Kalendrite, Ignatius)
2. Ore ignores any harvest level set in config, even defaults=> any version is harvest level 0, even granite versions (Cobalt, Shadowiron, Vyroxeres, Alduorite, Ceruclase, Midasium, Vulcanite, Sanguinite, Eximite, Meutoit)
3. Small ores work okay (config - 1), main ores are always level 0, even granite versions (Prometheum, Atlarus)
Using latest 5.09.11 if that matters. Strange thing is that some of GT versions of Metallurgy ores work okay, some not. Added this issue to your github
And another Q: i see that GT 1.7.10 ores use textures by type rather than one by one basis (as in 1.6.4), and only color changes. Is there still any way to specify texture and/or color for each ore? For example i want a few ores (coal copper tin bauxite iron redstone lapis and diamond) to have completely different clear textures, i can change vanilla versions in texture pack, but GT's still have it's own, which adds inconsistency if i want to mix normal generation via cofh and gt gen.