what size is your front sprocket? You really shouldnt go smaller than 15 on the front...
1 down in the front is like 2-3 up on the rear. Most will probably suggest 1 down, 2 up for a 600, but that all depends on your bike and what you want it to do. Remember the more you go up on the rear (or down in front), the lower your top speed will be. But the acceleration is much better.
Ask yourself how do you want it to perform, compared to stock...
You want a hardened steel front sprocket, and an aluminum rear. Be sure to get a new lock washer for the front sprocket nut as well.
You should replace sprockets and chains at the same time, as a new/old combo will wear the new part out faster.
Since you will be getting a new chain and sprockets, consider getting a 520 conversion... The chain is lighter than OEM, but still plenty strong. Go with an O-ring, or X-ring chain. I recommend only a rivet style master link. Of course, if you get a 520 chain, be sure you get 520 sprockets.
or you could sell me the gift card for $50.