I think everyone has summed it up pretty well. I have a half a dozen larger GMC trucks simply because I have been in the trucking business for over 49 years and my first big truck was a GMC. Just about all of them will start, run and stop. But I don't go out on the street with them. I just enjoy having them around. If I want to ride around in an old vehicle, I have a 1956 Ford just like my wife and I dated in.
As for the wheels, 22.5 are comparable to 20" tube required. 19.5 are comparable to the wheels that originally came on a 1 ton 60 years ago. In my opinion, 19.5 wheels would look goofy on a 600 series. I have 3 600 series GMCs. They look right with 9.00x20 or better yet 10.00x20 or 11x22.5 in tubeless.
