I agree that it's very hard to hit a moving target at long distances, so the moving scenario is the same for both. As for the popping out and firing a shot and slipping back out of sight, I don't think the Panther's slight speed advantage over a KT will make a big difference in the peek-a-Boo scenario. Do You? [I yelild to your much greater GV experience and success ] Wouldn't the travel time of the round , possibly, make a bigger difference. What's the Muzzle velocity difference between 88mm AP and 75mm AP? Or said another way, what's the travel time difference of the rounds to cover 3000 yrds?
I did some "testing" in the DA with a squaddie of mine, and another tanker we picked up in the DA. Me in a panther vs them in King Tigers, I killed both of them twice, landing a total of 8 kills (for some reason, the other guy upped an M8, probably hoping to lure me into a trap).
Panzer IV vs KingTigers, I killed 3 KT's, a Panther, an M8, and two M3(75)'s.
Thus proving speed does not equal survival. It comes down to several things: Gunnery, armor/gun, and simple, good old fashion sneakiness.