One more thing to consider, with regard to objective size on a lightweight rifle.
The larger the objective, the more glass it has. Sounds silly, but ounces = pounds, and a larger objective lens weighs more than a smaller one
More importantly, the larger the objective, the taller the scope height needs to be to accommodate it on the rifle. That isn't so much a weight issue, but the taller rings might raise your scope height enough so that you lose a positive cheek weld on the stock. If you add in a canted base, that will lower your objective, thereby requiring even higher rings to clear the barrel. That cant also raises the eyepiece height. So, cheek weld becomes chin weld, in order to acquire a full sight picture thru the scope...
Lightweight rifles are tricky enough to shoot well, and especially so when its chambered in a big 30 cal. When you factor in not having positive, repeatable facial contact on the comb of the stock, the whole package becomes a recipe for lowsy shooting form and inaccuracy...
So, if opting for a larger objective scope and/or canted base, keep in mind that, depending on your stock's ergos, you just might have to address a comb height issue. Remedy would be to add some type of elevated cheekpiece or stock pad/pack to level your eye in the scope, and re-acquire positive cheek contact on the stock. Which, in turn, adds more weight back onto your lightweight rifle...
