I typically don't color any type of LOG footage in FCPX, but I will edit in FCPX. Since there still seems to be a growing number of people who edit LOG footage directly through FCPX's poor color board, I thought I would show a different approach. Instead of adding contrast, saturation, and exposure directly to the LOG footage, try transforming it first. Depending on the footage you're working with you might find that it could be easier to saturate colors, adjust highlights, mids, and shadows all without touching FCPX's poor color board.
You can download the FREE LUT Utility from MotionVFX (CLICK HERE) which has some nice built in options for quickly transforming your LOG to 709, but you can also import your own custom LUTS also.
FCPX doesn't really have a simple White Balance tool, and again i'm not a big fan of the built in Color Board, so I suggest grabbing a decent White Balance Plugin. This White Balance Plugin from FCPEFFECTS (found here) allows for more than just cool to warm. You can offset artificial color casts (green/magenta), set exposure, and also tweak individual RGB values within Highlight, Mid, and Shadows. Again very easy tool without having to deal with FCPXs color board.