Wintec to Western gullet sizing

I ride my boy (QH) English in the medium wide (blue) Wintec gullet right now and he does fantastic in it. We've never had any issues with soreness or pain. Anyone have any experience with what size that might be the equivalent of in western saddles? I was thinking semi bars just because he doesn't seem as 'tank-like' as some of the other Quarter horses I know and he has nice withers. I have friends with western saddles I can try out too, but I'd like to have a general idea of what might fit before I go looking.

.

Using the Wintec Easy Measure Gullet Gauge their Medium relates to a Semi-QH 6.5" Gullet in Western.

That being said there may be other factors involved in a good fit, such as rock in western bars and flair of the bar, but it would be a good start conversion wise.



.