another grading question

I have a multicam edit, some shots were done on 5ds some on 70s - even though I recorded with the same colour settings, the 70d footage is much yellower.

Anyway I'm trying to match the footage in FCPX, and finding it quite difficult. I find the workflow quite tricky.

Is it possible to have 2 clips open and visible, with waveforms for each also visible?

Yes you could utilize the Event Viewer for this and turn on its scopes under the Window menu. This would work best if you were grading within the Multicam clip, otherwise the Event Viewer won't reflect your work. But for your situation it seems like this will work fine.

Thanks for that - the event viewer works great. No need for scopes though - I bought Hawaii Automatch, and I'm blown away by how good it is at matching footage from different sources. I'm sure it's all achievable using the built-in colour controls, but what a time saver!