I don't get it.... I've owned QH's, my boarders are QH's and I own a Morgan right now and it would be like comparing apples and oranges. They're completely different, not just in their build but in attitude and personality.
My Morgan is the same height as a QH I have boarded with me (both very well bred) and there is zero doubt as to what tack and things go to which horse. I could stuff 2 of my Morgan in the QH's halter, her blanky would look like a tent on him and his girth is probably 12" smaller. Morgans tend to have a more refined head and a finer build while a QH is stockier.