What would be the ideal size of a child rider when on an Arabian horse? Also, would a 1.5 metre child be too big, too small, or fine for an average sized Arab horse (from about 14.1 to 15.1 hands high)?
forget about the whole "arabs are high-strung" thing. just like any breed, it varies from horse to horse and in fact most arabs (especially mares) are very fond of children and take special care of them (mares were literally brought into the Bedouins' tents as babysitters).
a 1.5 meter kid is definitely not too big for an arab (as long as the child is a weight proportionate to height). i'm 1.7 meters and had a 14.1 hand arab that i rode dressage for years.
I hope it's a very calm Arabian to be putting a child on it. They can be a handfull.
The child would probably do better with a 14.1 hand arab. It would be able to ride it.