An important consideration when avoiding tennis elbow while woodworking, along with bench height, is the grip with which you hold your planes. If you have a death grip on the tote, you are likely to be over-tensing the muscles around your elbow, leading to problems like you have described. This is similar to a leading cause of tennis elbow in recreational tennis players, gripping the racquet too tightly. Also happens in military pilots, I have been told. Using improperly sized gloves can lead to overgripping and, in turn, tennis elbow.
So, after fixing the bench height issue, take a close look at your grip on the tote. You shouldn't need a death grip on it. If you still can't plane without pain, maybe try making a custom tote? Perhaps a little larger so that you can get a good grip without really holding on.
Just a thought, best of luck.