I'd just leave it as it is at the moment. You'll probably find that it will be a bit convex once you put it together and set it up with a low action (but then take the strings off). I normally find that a neck set flat before stringing, will normally take about 1/2 turn clockwise to get it roughly in the right place with strings on.
It should be a dual action truss-rod, so you should be able to give it both convex and concave shapes if you want to.