I'm not so convinced that wheel size makes a difference. I once rode with a woman who was riding 650's, same as me. She probably outweighed me by 50-60 lbs or more. I'd pedal like crazy to keep up, she'd coast, she always beat me to the bottom of the hill.

Last fall I took a 10 mile spin on a bike with 700c wheels. I didn't go down hill any faster on those than I do on my 650's.

When I ordered my new bike I asked if the sloping geometry would make me faster downhill. The answer was, no, weight makes you go downhill faster.
But, I can climb a lot better than most people.

A couple of years ago my SO and I did a tour in Nova Scotia. One day we were on a route with a series of rollers. He'd take off, be way ahead of me, I'd catch him about 1/3 way from the top of the hill. As soon as he crested he'd go flying down. I'd catch him again only to lose him. It was cat and mouse all afternoon.

On an organized ride I was climbing a hill and this very hefty lady was ahead of me. I easily caught her and started down the hill. Soon she passed me, she got near the bottom, didn't start pedaling and she kept going! She coasted for a mile and a half! Meanwhile, I'm behind her pedaling like crazy to catch her again. I just couldn't believe how long she coasted on the flats. I'm still not sure how she did that!

BTW, I'm now running 90-95 lbs in my tires. Seems the trend is to go with less air. Even Lennard Zinn recommends less.