I have to edit a video project (lectures) which had two cameras:
EX3 shooting 1920x1080p (25fps)
Canon XL1 miniDV 25fps

The main cam on speaker was the Sony EX3 (1080p)
Cutaway scenes and wide angle by the XL1 (DV) in 16:9 mode (I know not true 16:9 but the cam was set to that)

The end product must be on DVD but it should be best quality for PAL land.

What should the project/sequence settings (Premiere CS5) be to mix the two formats for best results to DVD as final medium?

I am editing on Adobe Premiere CS5 (have the CS5 Production Suite). No fancy effects apart from slight color correction and crossfades between two cams now and then and titles on end product.

I have heard that one should downscale HD footage first to SD but that seems only to be applicable if HD was interlaced. So this does not seem to be needed.

I intend to edit in Premiere CS5 and then use Media Encorder/Encore to DVD. What should give the best results?

Thanks for a wonderful forum!

Use SD PAL (720 x 576 25i) and use motion/scale to downsize the EX3 material. Your delivery format on DVD is the same.

Thanks Harm! I'll do that!
Thanks for the advice! Much appreciated!