I am using 2 different scales over the C7 chord. First, I use the C Lydian Dominant scale. Then I play the "wrong" scale - Bb Minor Pentatonic (still over C7) but it sounds cool! Why is that? Well, it's because the minor pentatonic one whole-step below has notes that fit into a C Altered chord, which is a common chord to use in the last bar before you go to the IV chord (F7 in this case). Capische?
Any time you have a Dominant 7 chord (I chord) and you are approaching the IV chord next, go down a whole-step and play the minor pentatonic, and resolve to chord tones for the IV chord, and you're good! Cool ay? I learned this trick from Scott Henderson.