Another problem with the Wintec saddle was that there was a TON of wither clearance. It has about four or five finger clearance. The Circuit one has the acceptable three or four finger clearance.
The last information I can think of about the Wintec saddle's problem is that the back of the saddle doesn't sit flat on her back until I sit in it.
Lots of wither clearance isn't necessarily a problem in and of itself, but it can be indicative of the saddle being too narrow. You said the Wintec was an extra wide, which I would expect to be too wide for an Arab, but it does look like it's sitting too high on the panels, which would indicate it being too narrow. Does it have the interchangeable gullets? If so, I'd double check the size of the one that's in there.