I would be extremely surprised if he is a true 19.1hh. Most sticks don't go up to that height so I bet it is more guess work than scientific assessment! There are a lot of people with 15.2s that they insist are well over 16hh.
we have got a few 18.1 horses at work, we did have a 19 hand horse that we had to get rid of because it couldnt fit in the boxes, i wud seriously have a think if u r going to want to take him anywhere cause u will really struggle to get a box that he fits in.
apart from that bigger the better
ps just looked at his pic and it is hard to tell but i would have said he is only about 17.1 17.2