When I began the project I skipped using any sequence settings. I then imported a clip with 29.97 fps (40 min long), and later a clip with 30.00 fps (37min long). They're being synced together and edited. They both run very smooth in the timeline, and I can't put my finger on anything innacurate.
Is it worth matching these 100%?
No, not really. You won't see the difference unless you are trying to match them up exactly to both been seen at the same time. I believe you can just modify the 30 fps to be interpreted as 29.97 and should do the trick for you.