17" VS 16" Weight and MPG

[longlivekel]

Okay guys..
I have been sifting through all of these threads.
Unless there is a thread I skipped over that can help me out.

I am looking at getting the best MPG on 16"s or 17"s. (prefer 17s)
I have 17"s currently and want to swap them out cause they are ugly as hell. Not sure if I want 16s or 17s. Some people say their MPG drop with 17" wheels. A stock 15" steelie and tire on a yaris is around 33-34lbs. So I need to make a combo that has the same weight (or close) but in 17s. I have seen some 17"s weigh as little as 15lbs (pricey) and 205/40/17 tires weigh as little as 18lbs.
A 205/50/16 weights around as light as 19lbs and up to 23lbs or so. I have seen some 16" rims at around 14lbs to 16lbs.

What is everyone getting MPG with 16s and 17s? what wheel weight? what tire weight?

Thanks a bunch!