Hi,
I've used valanced alloy or when looking for an original look, stainless, both with success. The stainless, I have further polished with mops before building to get the best finish possible.
I am in the middle of a restoration using a wider rear rim (see image). As Julian said, plus check the chain travel and chain guard. I had to move the guard about 1/4" as it was fouling the tyre. I feel the bigger rim and tyre does look good, when I have it running I'll let you know how it handles.
I use new stainless spokes and nipples. Whenever I've taken out the old they were chromed with corrosion around the threads.
I build my own wheels, it's easier than you think although Central Wheel Components built the rear wheel of the bike in the image. They have supplied parts for me in the past and I have never had a complaint.
Best wishes...