MA40 MB is cool. . . but just too tight to get a tyre on. . .
Yup, the campags are mega cool, and IIRC, the stheno is under 400g. And the concave does give a slightly larger braking area/ more time between adjustments.
But for me, the Sun zero degree/ lite was a proper rim, box wass, eyelets, machined sidewall- all the stuff it took mavic ages to catch up with, which is why it still lives on after 15 years. Around 420g, its 20 g lighter than a 231. Post 231 era, is for me, too new. You'll be talking compact drive next. . .
If you can find one of the tew tungsten caride coated zero degrees leaked out, you'll have a rim, that if well built, should last forever. ..