Please, please don't put risers on this bike. I realize you have a bit of a back problem, but if you just run bullhorns or road drops you get about the same upright position without butchering a classic bike.

Going from 42x16 to 42x19 or 20 is a HUGE jump.. I'd get a 17 at most.

I understand your distrust of clinchers, but tubulars are actually better known for flatting.. you are probably right that you have better control after you flat, but rarely does this make that big of a difference. For city riding, clinchers are nice because you can quickly patch a tube or swap it out, whereas with tubulars you're gonna have to walk unless you have a spare wheel. Tubulars do ride much smoother for smooth roads and tracks, and they are nice and lightweight. Oh, and cornering ends up being about the same if you have proper pressure.

You're probably distrustful because of the old non-hooked rims that had pretty serious problems, but now the hook is much larger and clinchers are much safer.

I'd get a tough clincher wheelset for city riding, and save the track handlebars and tubular wheelset for the track or a nice smooth bike path.

Just some opinions.. of course you're free to do what you want.