So you did a pretty good job... here's a few things I see... her humorous is actually a little too long, but, not so much so that I wouldn't say it's possibly distortion from the photo. You don't want that humorous longer than 60% of the scapula (that was my "late" note... somehow I missed that the first time around). I'd also guess that her shoulder slope is being distorted a little because her front end is turned a little away from the camera - so the angle and the length are going to be distorted a bit too (hence the importance of a really GOOD conformation shot over those "it'll do" photos). A steep shoulder is often found among the draft breeds, so it wouldn't worry me too much anyhow... but the closed shoulder angle does concern me, a bit, because it is paired with a steeper slope. (as a note, you had her point of elbow right the first time, making her shoulder angle closer to 80 degrees). Using my top of wither I got a shoulder slope of 50 degrees though - so that's not SO steep.
Her forearm actually isn't that short at all... at 77% of the humorous length it's well within "adequate".... however, I got measurements that indicate her forearm is closer to 85% of her humorous length, which is more than "fine".
Her back is a nice length, and her ribcage length is showing that her loin is also short - she has lovely loin girth - which adds support to that strong loin. It ties in well to her wither and to her croup. If our hip dot is in the right spot, her LS placement is great as well. Her back should never be an issue.
Her hip construction is nice as well, especially for a draft horse... however, I have a horrible feeling that if we backed up that hind leg so the cannon was verticle she'd lose a lot of angulation to her hind limbs, and sadly become post legged (I might be wrong, that might be the angle of this shot too). If that happens, we'll probably see a shift to the pelvic angle as well - making it more typical for a draft and a little less ideal as a riding horse (not always, but post legged does seem to affect the tilt of the pelvis a little. Post leggedness is one of those "sad" conformation faults, because it takes away from the rest of the "good" this horse has in her hindquarter, so let's hope it's an illusion.
Overall, I really like this Perch mare though.