I'd still see if you can get on a fit bike and play with the measurements. Call CycleSport or someone local and throw them a few bucks to play on the adjustable bike, or go get a fit. I'm almost the exact same measurements, and inflexible as hell. I'm on a Felt 56cm with a 14cm headtube and 30mm of spacer/cone. I couldn't ride a 57+ comfortably at all. Every fit I've had, had come up with a 56cm TT and 100-110mm stem. The cost of a true fit would be beneficial in the fact that if you buy a Kestrel in a 57 and it's too big, you'll lose that money vs getting a fit and finding a bike that actually fits you.

Here's mine, which has a larger stack of spacers that I would like, but I'm inflexible and any longer would be uncomfortable to me.