Assuming the proper tires and rim sizes were available, 15's would be the ideal combination all around, and a properly forged 15/16 will still weigh all the more less than a properly forged 16/17 comparable rims. I'm not saying there is an appropriate all 15" or 15/16 set of tires and wheels, but i am saying that fundamentally (it's physics) it should be better. Look at any true over the top race car from F1, nascar, to dragsters and they all the smallest rim that'll fit on the brakes. LOTS of sidewall.
I think some of the creative brake cooling options that some people have done here are a more elegant solution (although i'm not a brand guy, it's a very "lotus" idea. Instead of adding bigger brakes, add more cooling... which will likely weigh less and enable other performance features like smaller rims. The problem isn't the brakes ability to stop the car, it's their ability to disipate heat. Treat the problem not the symptom.