Hi everyone, I enjoy tennis but I'm not knowledgeable about it that much, however my girlfriend loves it, and plays it, and she has always said she wants to get the Babolat AeroPro Drive GT Racket next year when she can afford it. I've decided to get it her for her birthday in a couple of months time as a surprise. Can anyone help me with 2 things...? 1) Head Size/Grip Size There's 5 options, but can't find explanation as to what each number 1-5 mean and what difference it would make. 2) Tension This box has a ? in here and I don't have a clue what I would put here. These might sound like stupid questions to people who understand the sport and buying equipment for it, but to me, it's all confusing. Any help on this would be great, because the only person I know who could help, is the person I'm buying it for.