Just to add to the answer.
If you want to do PAL resolution projects then set your project up to 768x576 and make sure you interpret the footage as square pixels in After Effects.
This will make your animations look perfect when you put them into a PAL resolution AE composition.
It's a square (computer) v. non-square (video) pixel thing that we don't need to get too detailed about here.
Cheers,
Ben
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