As Woks said, there's normally a set of rough strings that comes with the kit and PBG add in a set of Ernie Balls (which may or may not be to your taste) which are a lot better than the kit set. So use the kit set for initial setting up and then swap to a good set for final intonation.
The important thing to do is to get the bridge in the right place. With a Strat, you can't really go to far wrong with the backwards/forwards location as the trem block limits too much movement, but you need to get the side to side positioning right so that the strings run down the neck correctly, and don't end up over to one side or the other. You might be able to move the neck slightly by easing of the neck screws and holding the neck over to a side to try and correct this, but there's normally only very limited scope. So an initial bolting on of the neck and using strings or twine to set the side to side position is very important.
Last edited by Simon Barden; 21-04-2017 at 07:11 AM.