I Don't think pedal float makes any difference in how fast you can click out. I do think pedal float can save you a ton of agony and pain down the road. (pun intended) If you are doing any serious mileage, you need to give you knees every advantage possible. With your size, you can generate a lot of power, but if that power is put through mis-aligned feet and knees, you will only damage yourself.

Since you are new to the sport, you should take extra care no to go out and Hammer your self right away. You need to take it easy, and work on your position carefully. It is the only way to avoid injury if you plan on really packing on the miles.

Regarding the Shoes, all mine have either been French, or Italian. I did see a pair of Nike Poggio II's that are pretty damn trick, but they are $$$

Shimano makes decent shoes, and I think they have a couple of pairs that are not priced out of this world. My suggestion to you is simply try on as many pairs as you can, find some that feel snug in the heel.

Charleston eh? I live in Savannah, If you ever come down this way, lemme know. I'll ride with ya.