You need to re-address the collar on the NECK of the brant. It is a LOT lower than you anve indicated. Also note, the atlantic has an incomplete collar. The brant might not care, but you will eventually do something about that.
Nothing lasts forever, well, that I am aware of, so be prepared to do occasional retouches on the stool. You probably do not need dull coat, as the images you provided appear quite matte. The only gloss part of a brant is its bill.
If you have a specimen, or access to images, check the collar.