As far as I know, the same encoding engine is used in PPro and Encore
As a matter of personal choice, so I do not have to "fiddle" with export settings, I edit AVCHD in PPro and then export to widescreen DV AVI
I give that DV AVI to Encore, and have Encore set to "automatic" transcoding to calculate the "best fit" of video time to a single or dual layer DVD
But, as I said, that is my personal choice so I don't have to get into "bit budgeting" and MPEG2 DVD export settings
we are recording in DVCPRO50 720P.
I don't believe that's possible. DVCPRO50 is a standard definition format, meaning 480 for NTSC or 576 for PAL. To get 720p you need to shoot in DVCPRO HD.
Personally, I'd shoot in 1080p/24N for anything but sports. For that I'd use 720p/60. Both are high definition and have to be scaled down for DVD, but the advantage is that you leave the option for Blu-ray possible. If you shoot in SD, then Blu-ray is pretty much off the table forever for that footage.