If only there was a manual. I've searched for a tutorial on using DVEs but there doesn't appear to be one. Furthermore, the tutorials appear to be for the beta version that seems to be somewhat different to the latest.
I guess this will take a lot of precious time to figure by trial & error.
Is there a manual with the Pro version?
There is a manual. Go to the top of this page and it's in /downloads/documentation.
There are also some other documents with hints and tips.
I have been able to work without problems in both PAL and NTSC with images up to 12 MP (4000x3000). I have not tried with larger images. The only issue is that I mentioned earlier.
I think the optimal size of an image for the purpose of panning depends on the duration of the movement and how smooth you want it to be.