Laz, the general consensus, among wheel builders, is that the valve hole should go where there are two spokes parallel. You can see on the rear it is in the right place, but the front is wrong. It's purely an asthetics thing, but it would wind me up no end. It makes no difference to the strength or performance of the wheel.
PS nice wheels!
Yes, it is a combination of aesthetics and necessity to keep the area clear for the valve in highly congested 36/40 spokes wheels.
However, other patterns improve slightly the wheel balance at high speed, especially if using those modern long valves on light wheelsets.
Don't aks me why... just an empirical observation...
Re. these wheels, I prefer to build the pulling spokes "head in", at least on the rear drive side, but again, it does not make a big difference.
Have you punched the spoke heads in place?
The hubs are just beautiful