Many thanks for your comments.

There are two major reasons for converting to 700C:
1. The other road bikes in my household are 700C, and I don't want to keep several different sizes of tires around.

2. I don't care for the straight-sided Weinmann rims. They only hold 70 lbs pressure with the Paselas I have installed. I would prefer hook-sided rims (vintage Mavic clinchers or Super Champion 58s -- both of which are difficult to locate) which would hold more pressure.

I could buy some double-walled rims (which look pretty decent) from Velo-Orange in either size. Anyone have any other recommendations?

I already have a decent set of Weinmann 610 centerpulls, and I was wondering if anyone out there has put 700C wheels on a vintage Paramount that was equipped with Weinmann centerpulls (IIRC, Weinmann centerpulls were standard on some models of the Paramount, so the vintage purists out there shouldn't have objections).

Also, I would like to build up the wheels myself. I have replaced many spokes (mainly rear wheel) in the old days when I used to do loaded cycle touring, but I haven't built up wheels from scratch. My old Wheelsmith wheels (from the shop in Palo Alto, CA) on my old Trek are still straight and true so I haven't had to replace spokes in awhile.