[Closed] What headset for Giant TCX0 'crosser

I bought a TCX0 frame off the 'bay earlier this year and can't figure out which headset I need for it!

The head tube is relieved by about 1cm at both top and bottom so it looks like it takes a semi-integrated headset. However, the Ritchey WCS Zero Logic one I bought will not press in - the cups are too big. I bought the Ritchey because a friend's Giant Bowery has one, and I assumed it would fit the TCX ... 🙄

Anybody know what type or model of headset I need?

I'm also missing the integrated seat clamp/cable stop. The top of the tube measures 35.0mm with calipers. Is this likely to actually need a 35.0mm clamp or is it within the errors of 34.9mm clamps, which are far more commonplace?

Cheers, Gareth.