I would definitely go with a harness and leash. A harness is much easier on
the cat. I always slip one through the collar just in case they back out of
the harness.

My little kitten was all teeth and nails when I got her and she can also be
affectionate. I do what comes naturally when she hurts me which is to yell
"ouch!" and put her on the floor. I think she is becoming more gentle, now.

Barb