I definitely think you need a testimonial from a woman for your women visitors. However, I think her boobs are a little bit too big for a testimonial image. It could turn potential women customers away for various reasons such as insecurity, etc.
For the men, if they are professional and intelligent, seeing boobs that big might instantly make them think, "Okay, all the testimonials on this page are fake, I doubt this product really works." I mean, we all know the boobs are fake, so why couldn't the testimonials be considered fake? LOL. This could go the same way for women though too.
These are only my opinions, but the best advice I can give you is to get inside of your visitor's mind. It might be hard from the start since you do not have any sales traffic going to the page yet, but make sure you track and analyze your stats meticulously. After a while you will be able to find trends in your traffic and in your visitors, and then you will be able to "learn" your general visitor and target them appropriately.
Good luck, and let us know if/when ClickBank approves it!
