Followup: I spoke with Brett today. The StarOne/Menace forks are 2", so taking into account the vinyl, Mike's measurement sounds accurate. So perhaps not wide enough for the beefy foam type boards that Mike uses. I can attest they fit Inland Surfer and CWB surf-style boards.

Skim boards fit in the standard wakeboard forks.

Lucky that I have a z5 cargo bimini rack in case I buy a thicker board down the road.