Alloy nipples in a non-eyeletted alloy rim. Not a combination I'd go for. No matter what prep you do now, a year or so down the line when the nipple prep has washed off, those nipples will stick to the rim and you'll never budge them.
Alloy nipples are great for new builds that you know are only going to be used for a year or so before being upgraded or in decent SS eyeletted rims but not for retro stuff that you want to hold on to as long as possible.
Edit: and before anyone asks, I did build wheels professionally for a number of years, not just spouting un-informed views!
Dead right on all points, but you cant ignore the fact they look cool, and as such I use them and trust the quality of my initial build to last