JHPSTANG

I'm hoping someone out there with a 67 convertible can help me verify something. I've tried two convertible top boots, and they didn't fit in the middle. Could someone please measure from the center snap on the body to the channel on the top of the back seat, and tell me how far that should be? The top boots I have gotten (TMI) have been almost two inches short of fitting in the middle. The rest of the snaps seem to line up, but the middle three don't quite make it. Thanks!