stripe question

[Ricoch3T]

Just trying to get this straight before I do it. I plan on laying some paint this weekend (my first time) and I have everything ready other than...



I've been told putting the stripe color down first then masking it was the way to go.
My main question is what grit should I use to scuff off the excess paint in the unmasked areas? I'm guessing 600 since its the last grit I used before color. And if so should I do it wet or dry? So far I have everything finished in 600 wet.
And if this is the proper way to do it... whats the best way to clean up before I spray my main color on the body? I'm thinking if I sand it wet then a quick wipe followed by the air will do but what do i know?!? lol.