A proper CMX3600 EDL should have reel names and TC for each shot. Do this in FCP by selecting each shot used in your sequence in the bin and adding reel names and TC to those shots. Your sequence should be conformed to a single layer. If multiple layers are required you will need to export an EDL for each layer.
Make SURE your reel names are comprised of letters and numbers only, and that they are 8 characters or less in length. Make sure you have no two shots that share TC on the same reel. Also, get rid of your audio on the prepped sequence and instead just export your rough mix as a wav or aiff and send it along with the edl. When exporting the EDL(s) turn audio mapping to none.
Be sure to start your program at an even hour and to include a 2-pop frame (in the picture) and sync pop (in the audio) exactly 2second before the even hour.
You should include a reference picture quicktime with the edl and roughmix audio files.
Another thing to make sure of, watch out for any single shot that has cuts in it for no reason. If you’ve got a shot in your sequence that has a cut right in the middle, take out the cut. There is no reason for it to be there. I dont understand why editors do this. So irritating.
I can tell you that there are very few things during the course of a day at a vfx/grading shop that come anywhere close to as annoying as badly prepped edl’s from the offline company. Your finishing artists and colorists will be much kinder to you if you can master the art of prepping an edl 🙂