It's really important to clean the screw and the inside of the shaft really well with motor spray, so the loctite will stick and hold them together.
When you put the loctite on the screw, spin the screw across your fingertip to wipe the excess off and leave loctite only in the troughs of the threads. Crank the screws down tight, just don't strip the head of the screw!
You can let the shafts sit for a few hours for extra insurance, but you shouldn't really need to wait for the loctite to dry. It's realistic to say that you could make changes at the track and they will stay together.