At the risk of being "you don't want this, you want that", I do have to ask, why not drops?
They give you a choice of hand positions (on flat bit, on hoods, or on the drops proper), and if the flat bit is around level with the saddle, or even a bit higher if you prefer an upright position, there's a lot of options.
With drops, you can tuck down out the wind, which can be demoralising on the flat if there's a headwind, quite apart from going faster. It's a mistake to regard drops as a "racing" or "lycra boys" thing - flats just mean no choice of position, and putting more effort in to go slower.
If you've a bad back or whatever, then none of the above may apply of course, and you may already have thought it through