If there is one person who knows about colour correction in FCPX it is Denver Riddle. He's published a free 12 minute crash course designed to show the new colour wheels and curves in 10.4.
When Final Cut Pro X was first released back in June 2011, there was a certain group of editors & colourists that scoffed at the Color Board. Not Denver Riddle from Color Grading Central.
He produced a series of colour correction tutorials using the new Color Board that when published on FCP.co proved to be very popular. He certainly changed a lot of people's perception of the Color Board's usefulness.
He is also the author of Color Finale, the first colour corrector plugin for FCPX to feature curves and wheels. Now that 10.4 contains enough wheels, curves, masks and adjustments to keep most colorists happy, some of the features of his plugin have become redundant.
There is still a difference as Denver explained:
There are still some advantage in Color Finale like LUT previewing, exporting LUTs, Xrite color checker, Tangent devices support, color management and group grading.
So Denver has decided to transfer his knowledge and apply it to the internal colour correction tools in FCPX. He has published this 12 minute crash course to get users up to speed quickly with the new features in 10.4. A slight hint here, don't be put off by the countdown if you click through to his site :)
A big thank you to Denver and hopefully we might manage to persuade him to publish a few more tutorials.