[Closed] Guidance? Which headset for Cannondale Trail 2 29?

Hi all-

Have a Cannondale Trail 2 29 (purchased off this forum - huge thanks to the seller) - needing a new headset. Current headset is a Tange Z-step for 1 1/8" steerer, non-tapered.

I'm confused about all the various semi-integrated options - on CRC I see 44mm cups from Hope([url= http://www.chainreactioncycles.com/hope-integral-semi-integrated-zs44-headset/rp-prod18084 ]http://www.chainreactioncycles.com/hope-integral-semi-integrated-zs44-headset/rp-prod18084[/url]), and Ritchey seem to do 46mm ([url= http://www.chainreactioncycles.com/ritchey-comp-press-fit-semi-integrated-headset/rp-prod39377 ]http://www.chainreactioncycles.com/ritchey-comp-press-fit-semi-integrated-headset/rp-prod39377[/url]). The Tange site is even more confusing.

Without me going to the shop to have them measure the inner diameter, does anyone know specifically which headset model I should be purchasing for this bike?