Your answer is in the Parlee website. The geometry of the standard Z1 is published as is that of the Z5. Look at the Front-Center, BB drop, HT angle and rake. The Z1 is more along your definition of "snappy" than the Z5. It's a trade-off.
Colnago only publishes the rider geometry, not the bike handling geometry; so sort of finding your exact size to demo you will never know how the bike handles before you put out the cash.

Ufgators, it's Tinea. No need to be smarmy.

And in case you've missed what a lot are saying (which it seems you have) the post below yours sums it up and should make it clear.

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Baum Ristretto, Baum Mondrian Corretto & the '89 Merckx! | "If you could eat it in one sitting, hold your line." | twitter.com/Tinea_Pedis

I see, my mistake.. thanks for the help

Handling aside(for what should be the obvious reason that custom will handle any way you want) you can also make the z1 stiffer than the z5 and or potentially a bit less stiff. Of course that doesn't mean much for folks that haven't had a ride on the 5 (with familiar wheels tires and pressures).

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charles@pezcyclingnews.com