OP has a bunch of questions.

1. How aero (or how tall)? With a well designed rim, i.e. Zipp or the like, you can get aero at lower than 58/60mm heights. I think it's hard to get aero benefits below that; just go light. At 46mm (Reynolds) I didn't think I got much more aero - my top speeds weren't much higher.
2. How tall to get aero? Well, first off, the front wheel affects drag more, so a taller front wheel makes sense. I used to ride a TriSpoke (i.e. HED3) front and a spoked rear (Eurus or Spinergy). Problem is the front wheel also affects stability, so going too tall can be problematic.
3. Rear wheel - you can go as tall as you want. I've ridden a disk wheel in back in very windy conditions, no problem. Put it on the front - it's a problem. So you can go 60/80/90/100mm, whatever you want. A tall rear wheel stabilizes you, at least in a straight line.
4. Crosswinds - again, it's also a function of rim shape, not just height. My 60mm HED Stingers feel fine in up to 30 mph gusts (albeit on flatter roads, so max speed about 45 mph). I felt just as insecure at 45 mph on my 60mm HED Jets as I did on my 46mm Reynolds, in similar conditions (extremely gusty winds - drafting an 18 wheeler).

If I were to get one set of wheels, if I didn't spend a lot of fun time over 30 mph (in other words, I try and go over 30 and it's a lot of fun, and I'll sacrifice 15 minutes of steady speed in order to get one minute of fast speed), I'd get whatever lightest wheels I could get, just because they'll lighten the bike, accelerate quicker to 40 mph, and not penalize me significantly under 28-30 mph.

If I liked going over 30 mph, even if only for seconds at a time, if I liked going as fast as possible, I'd get aero wheels, but I'd try and keep the weight under 1600g, just so there's still some acceleration in there somewhere. If I couldn't get that, I'd get light non-aero wheels.

I have light aero (60mm rims), light non-aero, and heavier aero (60/90mm front/rear), all HEDs, with all the aero rims shaped well for crosswinds. I prefer them in the order I listed them.