I don't really know about the cure time. The way the product works is to dissolve the PVC, both in the 'Schmear', which is just PVC chips, and in the surface to be repaired. Hardening depends on evaporating the solvent that dissolved the stuff in the first place. It's not a 'glue', where there is some sort of catalytic or chemical process going on, beyond simple dissolution.

Heat helps, or rather, warmth. The solvents are very, very flammable!

But, the thicker the 'goo', the longer it will take to dry. If you like you can put the mixed Schmear in a metal, glass, or polyethylene container, and add it in layers. It will keep 'in the can' indefinitely IF there is a tight seal preventing evaporation.

Sorry that I didn't think to warn you that it's not a quick fix, like epoxy would be. On the other hand, done right, it's permanent, if messy, repair. Epoxy would not be.

Something else I didn't think to mention, or ask about. You should see if you can tell WHY the Tee cracked in the first place. If it was freezing, no problem. But if it was some sort of stress, because of out of alignment pipes or an over-tightened fitting, you should do anything you can to reduce that stress.

Good luck!