So the headset of my cyclocross bike, a 2007 Norco CCX One, is quite the worse for wear. It needs a new one. I consider myself a pretty good mechanic as far as the actual installation goes and have easy access to the correct tools to remove and install. BUT despite reading and research for quite more time than it should have taken I've yet to make myself entirely sure of the correct replacement headset bearings.

The Norco catalog says Ritchey Comp 41.8/6.8mm. This looks like Campy Hiddenset dimensions to me but that just doesn't feel right despite all evidence pointing that way. Although it seems that Ritchey did make some Campy headtube compatible integrated headsets so it's not entirely unlikely.

I would really prefer to avoid popping these bearings out of the frame until I'm ready to replace them as they're in there quite firmly so I don't know the height of the bearing. As near as I can tell with some calipers the OD is 41.8 and the ID is 30.0, making the bearing 6.8 mm think which matches up with the numbers from the catalog. The upper bearing has printing visible that says "Ritchey 41.8 x 30.5." There are no visible cups or sleeves so it's an integrated system.

All the evidence seems to point towards Campy, aka IS42. Anyone know anything that might point in a different direction?

What would be the most cost effective replacement? It's a cross bike and it was raced several races plus many miles of singletrack and quite a lot of road miles (where I'm not very gentle with pot holes and curbs). Plus I'm a big guy (6'1" / 220 lbs) so durability would seem to take priority.