Wintec and leather
I bought a Wintec a last year and asked the same question of my saddler and they said it was just the issue of the leather marking the saddle, which I decided to take the risk on, because I hate Wintec stirrup leathers, I used them together and they were fine, there was a little bit of staining on the saddle, but to be honest, not a lot more than there would have been anyway.
I decided that as it was my saddle, and my comfort I would take the risk. Sold the saddle on fine too when my youngster change size so much it didnt work and purchaser never said anything about it.
I think if it is your saddle and you are happy with it marking, it is very much worth the risk.