I've got these Eighthinch cranks, and they're fine for the price. They're really about the same as any OEM crank, but would be perfectly suited to your conversion. The Tessa wheels would definitely be better than the knockoffs, but they also cost a bit more. The knockoffs are a good deal if you want an inexpensive deep aero section wheel. I have no doubt that the Tessa's will perform better.

I keep a digital micrometer handy for measuring posts and clamps, but if it's a steel frame, 27.2 would be my best guess. Take it to a bike shop and have them measure.