Get a frame with a 650c front wheel. 24" wheels look super aero but are a real pain and force you to ride far too low for any real city riding IMHO. 650c are also common enough that most bike shops either stock or can order good tires and tubes.

With a 650c front and a slightly taller stem, the difference in height between saddle and bars on mine is only about 1" more than my track bike, so its still a very comfy bike to ride.

The hardest thing, as you know, is working out what the effective top tube (ETT) length is on an aggressively slopped frame. Pursuit frames come in so many designs that I don't think there is a golden rule to say if you ride a 59cm then you need a...

Generally you'll need to add a few centimetres. I know my friend was looking at a frame with a 53cm ETT which had an actual top tube of 56/57cm. I'll measure mine when I get home and hopefully it may give you some idea.