I have tried to make a scatterplot of my hq tier versus quality of iron nugget synths to figure out if hq rates are flat tiers, first, or second degree... but I ragequit it after about 150 entries when ten synths over 400 quality failed to hq1.

I agree that it takes x quality to "unlock" hq tiers, but still have no quantifiable data.

And I wish mat synths allowed touchups or were more forgiving in hq rates.