[Eoin McManus] “What is the best settings to launch a FCP project editing XDCAM footage”
I hate “best” questions. It may depend on your full workflow as your additional information points to.
Generally if you drop the file on the FCP 7 timeline you’ll get a popup allowing FCP to use the sequence settings matching the source. What that is depends on the flavor of XDCAM you shot with.
[Eoin McManus] “some of the files were shot in 23.98fps, while some are in 30, all 1920 widescreen. Is there a way to import without having to render one or the other?”
You need to decide which way you want to go with this. This depends on how much of each you have as well as desired delivery targets. FCP generally does a poor job of “on the fly” 23.98 in 29.97 conversion. I believe it uses an “odd” 2:2:2:4 cadence whereas you would be better of converting to a 3:2 pull down cadence. This is assuming you want to work in 29.97 for 29.97 delivery.