I edit with FCPX. I have just been delivered footage - about 50% each - from a DSLR Canon, and and XDCAM Sony...
the colours of the DSLR look comparatively flat - and the shots in low light are really striking in how much more light the Sony caught.
And as much as I'd like to dump one set of footage - they are both essential....
Any advice on the best way to make the footage knit together well (beyond the simple match colour effect).
There are so many variables that there's no "automatic" way to do this.
I'd recommend using ColorGradingCenteral's Color Finale Pro because it has curves and vector controls which give you far more precision than the built in color board.
Correct a shot from one camera to be the "hero" shot. Save that setting.
Grade a shot from the other camera to match. Save that setting.
This is done before you apply any looks. Most important is shot matching.
Depending on what and how shot you may need to do the above for each two camera scene.