co-focus is pretty long lasting for a poly. And the thing is, the gut in the mains mitigates the dead feel of the poly to some degree. Remember, most of the feel of the stringbed comes from the mains, the crosses are more of the stabilizer in a hybrid.
That said, I found with the gut/co-focus set up that the cofocus would go through a "dying" stage around 8-12 hrs where I didn't like it so much, seemed to lose the control and feel, but once it got past that to the "dead" stage it would feel great again until the mains broke.
BUT... I've also moved on to a different poly cross, Solinco Outlast, which I feel always lasts the life of the gut mains, which for me is anywhere from 15-30 hrs. And the thing about Outlast, is it doesn't evelove through the different stages. It feels almost exactly the same from day one until the gut mains break. It's also a little crisper than co-focus which can be a little mushy on a flexy frame like the Tour 100.