With County, clearance totally depends on how its flocked and which tree fits. I thought my CWD (the 2Gs) had the same clearance as the Voltaire.
I would not buy the extra squishy foam without test riding first if possible. That is actually what my horse hated about the Blue Wing the most, I think. What started out as nice wither and spine clearance went squish as soon as I sat down, and while there was still clearance, there wasn’t enough for his liking. It basically squished right on down to where the regular foam was and so the fit was only as good as how the regular foam was placed. So, if it’s added just for shock absorption on top of the regular foam, well, I don’t buy that. I’d rather use a thinline or something.
Perhaps I’d use it for that area that tends to bridge when you’ve got a big shouldered horse who needs some lift in the very back but not a lot of foam in the middle to front … but be careful of the salesmanship on this foam if they can’t find you a demo with that configuration. Perhaps they can…my local Voltaire rep flew me out a saddle that was built up with more clearance for me to try because my horse doesn’t tolerate shims, so we had to try to experiment as closely to what would actually be built. Had to do the same with CWD but they had more demos locally.