Several old books, FWIW, have said to set the bars so the bottom grip below the bends angles up by 5 degrees, and to place teh brake levers so the tips are in line with the bottom of these grips. I find this looks good and is comfy in the drops if I have the right extension.

Others have said "level" and others have said point them anywhere between level and where they point directly at the dropouts. But why should pointing at the dropouts have anything to do with wrist comfort, for a person who rides several bikes of differing lengths? It should really be about your wrists, and ready reach to the controls, i.e brake levers.

Can be an issue for different bars. Cinelli 64s have the ramps pretty far sloped down in this setup, 66s (classic Maes bend, I think) a bit more level, and touring bars like Nitto Randonneurs still very level.

If you ride on the hoods a lot, rotating the bars does indeed affect the height of your hands, and thus affects your back angle.

IAB and John E have it right IMO: use your sense of comfort and ergonomics, and rotate teh bars so the bike is comfortable and most easy to ride.

Road Fan