Re: 520 conversion question
Tony @ Bluestreak is a good choice. But your 600 probably already has a 520 chain... :)
The ratio you are looking for will lose you a fair bit of top end but it's probably not speed you will use anyways whether you are on a road or a race track. It will definitely liven up the bike.
Re: 520 conversion question
If you do the -1/+2 your speedometer/odometer will be off 10%ish which means you will be adding that many extra km's to the mileage on your bike also your will be getting the wrong speed you are actually driving.
Best suggestion if your going that route is to get a speedoDRD or Speedohealer to fix that problem.
Also if you go to http://www.gearingcommander.com you can enter any sprocket info and it will tell you how much top end you will lose, new vs old ratios, etc..