No one I know has flown a twin as P.I.C. below 1000TT, even with the endorsement. There probably are stacks of people on here who have, though. Good idea to get used to the twin before finding yourself assymetric in cloud, I guess, but I wouldn't spend too much $ on it, cause I have a feeling you might well be in dire need of them once you're working in the industry.
Put it this way, you can get paid to fly a complex single without having to buy twin time yet, and that will also be advantageous to you for when you're actually applying to a company who operates twins. I find I need to be quite vigilant and 'with it' to keep up with a 165kt TAS single, which of course is as fast as some basic twins anyway.
520.