Here’s my idea. First you can make the PSD file any size you want (at least the HD res of your working timeline in AE of course). If you make the PSD larger than that, that’s great since you may get a better resolution response in AE when you are applying Cylinder and you can always size it down in your comp.
It would give you a good response to have your AE comp at an HD size relative to your main FCP footage/subject, say 1280×720.
In FCP use the 1280×720 or whatever your on camera personality is shot in. It’s just better to start with the highest resolution possible, or use it when you have it. You can then simply Nest your FCP Sequence into a 720×486 sequence or whatever your final SD size will be.
That’s my 2 cents
TimelineGFX
222Media.com
https://www.timelinegfx.com