re: 40mm or 50mm objective lens?

My dad, a lifelong deer hunter, has never mounted a 50mm scope or larger on any of his rifles. Besides the extra weight, you have to use higher rings and risk having to use a cheek riser to be able to look through the optic.

I rather a slim-and-trim 40mm objective from a quality manufacturer. I don't want a giant telescope monstrosity on my rifle and rather the slim and lightweight profile from a smaller scope.