Not to take away from the SV650 because they are great bikes and would be perfect for the track but a 750 is not 'too big'. I ride a 750 and it's perfect for me. Why? because I know that bike and every bit of the way it handles. I'm comfortable on it and that's what's most important.
If you can afford 2 bikes then go for it. If you have only 1 bike and you wreck it at the track then your street bike is out too, if you have 2 bikes you always have one to ride if that's important to you. All about preference and money really.....
