Black Country will build pretty much any saddle on any tree, but in its "original" form, the Ricochet was the Quantum built on the Wexford tree (Classic GP tree) and panels, but with a squared off cantle. And the squared-off cantle is what makes is the difference between the Classic GP ("general purpose") and the classic SC ("square cantle") tree. As far as fit and function, though, the trees are the same.
The AO AMS Alto fits my trainer's strangely conformed TB really well.
He has a HUGE wither, wide back, massive shoulders and a sway-type back. He is 17.1 and built like a tank - except that wither.
The AO AMS with a medium/wide (starting into work) or wide (fitted up) plate fit like a dream. Can't recommend that saddle enough. She has had him 14 years and always made due with corrective pads and such, but now we can just ride with a baby pad!