Personally, I'd also be considering the option of a switch to a freehub and a modern titanium cassette. Wear and shifting performance is far better than vintage aluminum cogs and you'll still save about 2/3 of the cog weight versus aluminum. Plus you get the inherent, superior design of a freehub. The only drawback is price, but then again, vintage lightweight freewheels are not cheap either and they are much harder to find, especially in good condition.