Yes, you did say this, but that’s not what you said Wendy was wrong about
2 horses who are similarly shaped is not at all fitting into the “the most versatile fit dressage saddle” category. The fact that they can currently wear the same saddle means they are not different enough to actually need a “most versatile fit” saddle.
If they both fit in a Pessoa, then look at Prestige - similar in shape, works with taller withers. Try a 34-36cm to give these horses some room to grow, using a thicker pad or a shim up front until they do. There at least used to be quite a few older Prestige dressage saddles out there for very reasonable prices.