Originally Posted by Saddlebag
It's not just a matter of weight but how it is distributed on the horse. A substantial woman carries a lot of top weight as well as her middle and out behind. This exceeds the area where a horse best carries weight as the saddle has to be longer. An english saddle, rule of thumb, should have a hand's width between the rider's butt and the back edge of the cantle. The length of the saddle would likely be too long.
Now that is a complicated and strange theory
A substantial woman could be 6' 4" heavily muscled, and have a small tush, not all of us are big bosomed and big butted.
Yes you make a valid point about length of saddle v length of horses back v size of riders butt, BUT generalisations just upset everyone.