The big guy does very well in CTR. He has a low heart rate and heat and humidity don't phase him at all. But I don't think he's cut out for endurance for reasons that don't have anything to do with his size. We did a couple of 50s last summer and he coliced after both of them; he has a history of gastric colic.
So far I'm very pleased with the 5 y.o. I bought him last Fall. Before I got him he hadn't been ridden since he was broke as a 2 y.o. I didn't ride this winter because it was so cold and the snow was deep and crusty. So we have along way to go in schooling and conditioning.
I love TBs but know the small Arabs are the horses to have for endurance so I compromised and bought a small TB!
My 11 y.o. son rides a wonderful 16.1h QH. They do CTRs and have always been 1st or 2nd.
BTW I have a good measuring stick with a level and stand the horses on smooth,level concrete so these numbers are accurate. Most people tend to over estimate their horse's height.
Mary Eaton and Kintyre and Seamus
Will Mueller and Finnigan (AKA The Mighty Finn)
Towner, ND