If the object ball is 2 feet from the pocket and cue ball is 2 feet from the object ball the margin or error is relatively large for a force follow shot. Now the same shot but 4' X 4', with a smaller margin of error, it would need more force follow due to the longer distance. My experience is that the heavier weight would give more force follow without without having to power the shot. As for the length of the extension, I feel it adds some stability.
As an example: A 9 ball break shot is not as accurate as a normal stop shot.