HI Bugsy,
I don't know of
HI Bugsy,
I don't know of anybody using tubulars on Cruzbikes (I bet there are), but it would be no different than on any other recumbent and DF (diamond frame - regular) bikes. There would be no reason to switch back.
As far as the gearing goes, if you can use the gearing seated on a DF bike on your hills, you'll have no problem on a Silvio. If you need to stand on your DF for a lot of your hills, then that suggests you might want to go lower on the Silvio. It is worth noting that unlike other recumbents, you can pull on the handlebars where you are effectively pulling the pedal into your foot which will give you a little more effective low end (almost but not quite the moral equivalent of standing).
I'm personally a crappy climber and I don't like mashing, so I very much like triples and very low gears. But I can't climb on DF bikes either.
Cheers,
Charles