Ok I've got a pair of the DA C35 clinchers which I get on fine with, when I fitted them I was disappointed to find they were 200g heavier on the scales than my old wheels so have been contemplating building up some Velocity A23's on American Classic hubs, CX Ray spokes with DT Prolock nips, 24f/28r. Part of the appeal is weight, part the wider tyre seat, I'm open to opinions on the build and ride of the Velocity rims (I'm 165lbs)

Physics say the wider tires are better in just about every way, with the possible exception of weight, depending on what you choose. What's your weight? 20/24 might be enough, allowing you drop a few more grams. You can also use the veloplugs on the Velocity rims, which may save you a few more grams compared to rim tape.

Personally, I could probably make cases for other hubs, but the AC will be light.

I'm 165 pounds & would probably run GP4000s with Michelin latex tubes, hadn't thought of the Veloplugs though, that & 20/24 could shave a bit more off, I've never been a kit breaker so don't mind going a bit lighter, I'm intrigued to try the wider rim.

I'm 165 too. 20/24 is more than adequate with a quality build. If you want to overbuild a little, just go to 28 on the rear. At least, according to every reputable builder I consulted when selecting my wheelset.