A: Crack fillers are designed to remain pliable, that is why it is important for the material to be in the cracks and not on the surface. Covering the repaired areas with a skim coat of trowel patch will provide a hard coating and covering any imprints.
A: Depends on the size of the gap. For 1/2" or less we would recommend Latexite Pli Stix. For cracks larger than an 1" we would recommend Latexite Quick patch.
A: I use the blacktop crack filler in the caulk tube. Tape off if you want a clean line. I do mine each fall right when it gets cool.