Ok, just one more update and then I''l shut up about it until I've actually built the damn things. I e-mailed Mack about his hubs and he gave me a near instant reply. Very nice guy and quick to send me a tech and pricelist. It turns out the ultralight version of his rear low flange hub (single sided) weighs just 190 gms, including bolts, washers and lockring! The AC hub's weight listed on their site was without all of this. And Mack uses bigger and better bearings, so the choice was easy!