Hey Pickle,
I have a pair of those 1.7 Ritchey Z Max WCS on my Dyna Tech right now!
They are super light [400g] and great in the current muddy wet conditions too.
In fact I remember that Sinnett said that Ade Timmis used to also run 1.7's
It seems that skinny tyres were the order of the day BITD.
Cheers,
Chaser.