I don't care who grinds the cams I Always degree in my cams and then tune the cams from there! belts are almost always different lengths. no 2 belts are the same. also cams gears coming off an assembly line have vary loose quality guidelines. also the alignment pins can be off. if you just put 1/2 a degree on each you'll end up with 2 to 3 degrees off on your timing. and that can mean hp loss. Sorry but I don't agree with just installing them the way the grinder set them. to many other variables come into play.
I kind of agree and I kind of don't.
There are tolerances, yes, however I think you might be on the VERY loose side of them. I've seen bad belts that can cause issues, yes. BUT, if you have 2 GOOD belts, they should be the same within a certain tolerance and they should stretch over a certain amount of time very nearly equally (taken up by the tensioner).
The cam gears are cast, so unless the mold shifts, it's going to be right. I literally had STACKS of cam gears for the 2.2/2.5 engines. If the part numbers matched, they ALL were exactly the same!
Yes, degreeing the cams in is a good idea, especially after they've been ground, BUT only for the purpose of setting them where the cam profile is supposed to be! You do NOT need adjustable cam gears for that! The make it easier, but they aren't needed.
I agree that after that, then you can mess with them to your liking.