I don't imagine you'd want a taller draft cross being as short as you are, I'd look for something shorter and compact in build. I am 5'4" and my 14.3 hand mare is just about as high as I ever want to have to throw my saddle! A western saddle would distribute your weight better, but as others mentioned they are also heavier. A nice synthetic saddle might be a good option, but correct fit regardless of if its English or western would be more important. There are plenty of horses that would easily be able to carry you, as redpony said look for something short backed and stock type, or maybe even something like a haflinger. My husband is around 220 pounds and rides a 14.3 hand quarter horse. He is a bit longer backed than we'd like but has never had any problem whatsoever carrying my husband even on heavy mountain rides. And my husband uses a big old 42 pound ranch/cutter saddle on him, but it fits him like a glove.