Well I’m 5’3", and have ridden big horses as show jumpers in decades past. 16.3 and 17 hands. They were fine, I was tiny on them. I didn’t choose them for their size, it just worked out that way. They were either purchased young, or off the track. My current mount is a TB mare, home bred, we raced her for three years (owner/trainer), then I started jumping her. She is 15.2 hands. She takes strides out down lines if I don’t watch it. She mostly does the 3’6" jumper divisions, but jumped up to 4’ 10" in a 3 bar competition last fall. Put 6" of air over that. I don’t know if she truly is that sort of horse, international calibre, on a full course, but she has enough jump for me in my old age.
Being large has it’s advantages, makes the big jumps look smaller. But being small also has it’s advantages, my current mare is so QUICK, because she is smaller. She has been described as being “cat-like”. Practically anything large and lumbering, we can beat on time in a jump off.
A good horse is a good size and a good colour. They come in all shapes and sizes, and breeds. People who are breed snobs, or size snobs, are fools. There are lots of fools around. If you are looking for a jumper, it has got to have jumping talent, soundness, a good mind- careful and smart, courage, and scope. It must have a natural 14 foot stride, that can be easily shortened to 12 feet, or 10 feet. These are the things that are important, not it’s physical size. I thought that Eric Lamaze pretty much publically proved this quite convincingly in past years.