Add your abody driveshaft length for quick reference

73 Duster 108”
833 trans
8.75 rear
I’m at 48.25”. Touching the back of the Brewers 833 seal, it’s 49.25. Driveshaft guy said to go to the rubber and subtract 1”. This puts me a little short of the factory 48.9”?? I’m not familiar with this type of rear seal. This is Leaves me about 1” of yoke showing per the driveshaft guy. Is this ok? Too much? Split the difference ? Thanks.