Hm-m-m.... My paint has high withers, so I was looking for the saddle high enough at the pommel. I ended up with Alamo pleasure saddle, which has high pommel and gives plenty of space for the withers. Another saddle, which would fit her there was Billy Cook's (I also liked it a lot). Tex Tan was too low for her. Same with Abetta (which didn't fit even my lower withers qh). If you horse has high withers I don't think flex tree would work for her. People I know has ottb also with very high withers. I know they got Big Horn.
Saddle shopping is real pain in neck, so good luck!