Right, you definitely shouldn't request all 200GB at the same time, because it'd be expensive and also because you probably can't download all 200GB immediately either.

Arq (a backup app I wrote) takes a transfer rate from you (guesses your max transfer rate as a default) and then requests enough to be downloaded in 4 hours at that rate. 4 hours later, it requests another 4 hours' worth while it downloads the first 4 hours' worth, and so on. This mitigates the peak-transfer fee.