To me, it was not all that "obvious" years ago. The question is what weighs more in that portion of the circle. Rubber that goes all around and has Steel belts vs just 5 or 6 Aluminum Spokes that only cover a portion of the same area (but along with a longer circumference for the Rim)?
There are some very old post with Rim Weights listed. In comparing tires, check Tire Rack - Your performance experts for tires and wheels. They have excellent details. Just be sure to get exact same tire model, as sometimes a mfg offers 2 tires with different weight capacity, even though exact same size. P Rated vs D or E. I am going to guess only a 5# difference per tire.
Large rims are all the rage in Appearance, and Drifting. But road race, track and street, still favors a somewhat normal rim. Weight further out (oversize rims) puts more load on the vehicle. Standard size allows the tire more cushion to the ride and better protection of the rim from pothole destruction vs stiffness. Large diameter tires also drives up tire cost and rim cost dramatically. I've switched from 17" to 18" (larger front brakes available), but have no interest in 20" for my purposes.
That's exactly why I'm asking. Unsprung weight affects handling and fuel economy so when the time comes for me to lift the T and go to 33's I want the lightest option available. I was hoping that someone maybe would have had this scenario and weighed them to see.