This is, I believe, the most significant of the replies posted above. I think racquet weight, grip size, and string tension are the important factors, out of which string tension is the most important one. Tennis elbow is just the inflammation of origin of muscles, tendons and bone at the outer elbow caused due to abnormal pressure. This is reduced if you alter the pressures (mostly stringing, grip size). Its more of a trial and error and you need to judge what suits you.