Thanks for the feedback everyone!
I need to get very high quality photos before I’ll offer prints of the painting. I’ll try to get around to that soon!
As far as the head size and everything-- the proportions should be fine, though I could certainly change some things. I obviously had to use reference photos for this, but was very sure to get far back from the model and shoot with a longer lens (a longer lens, at least 50 mm, at more than 10 feet will eliminate photo distortion in a half length figure). I then drew it by eye and then checked it in photoshop over the reference to make sure the proportions weren’t off.
I DID make the right shoulder tilted more, because I wanted the curve going from the hair down through the flowing drapery. A too box shaped shoulder could interrupt the flow of the curve. The width of the shoulder should be fine though. That simply would make the neck longer.
So, I could widen the shoulders a bit.
Faithsmind pointed out the level of the waist being too high, making the torso appear shorter. I think that could be it? You can see the nipple length is right (one head length down), and the elbow length is right (that’s by the belly button, about another head or so beyond the nipple). I think the problem is that the rope tying the toga is tied around the waist, up by the belly button, and not by our beltline like we do today.
This is the old master painting I used as reference when making the costume, and you can see he made the rope above the belly button and not the hips/waistline like we wear our pants today. I think this may be the problem.
I could widen the shoulders a tiny bit, and then push the folds on the waistline down some in order to make the rope tie a little lower.