I'm surprised no one has said this yet.. So here we go.
Rifle with scope and regular rings in one hand, rifle with scope and light rings in the other. I bet the farm there is no one in existence who can tell the difference. Regular Seekins 30mm medium rings weigh 2.5ozs. NF Ultralight weighs 3ozs. My Burris Signature Series rings with Polymer inserts are probably behemoths tipping the scales at 3.9ozs. I suspect you may see a swing of 1 to 1.5ozs between the leading ring manufacturers.
With my 12lb rifle, gear, clothing, boots, food, water, ammo, etc, I'm easily at 25 to 30lbs. Which is my every day kit that I manage hunting elk and deer in the Idaho mountains (and I'm 55).. I dont notice a difference in a swing of 4 to 5lbs, let alone 4 to 5 ozs, which is so far under my radar I cant imagine a person who would actually notice it.
Buy the rings you want to use. The weight of a precision machined aluminum component isn't even remotely relevant.