All
I am considering a 20mm carbon tubular build 20 hole front 24 hole rear and I was wondering if anyone has had any experience building up the front wheel laced 1 cross rather than the more common radial or 2 cross
Cheers

Yes, I built my most recent front wheel 1x. The hub I used (White H1) has a reputation for going slightly out of round if laced radial. The wheel I removed it from was built by Troy Watson (Ligero) who had also laced it 1x, probably for the same reason.

It looks a little different from radial. Radial is easier to lace up because you don't have to think while you're doing it. Other than being a little easier on the hub if it's weak I don't think there is any functional difference.