Hi Ben,
The results will not be good. Encore (as well as Apple’s Compressor) cannot scale HD footage to SD (Standard Definition) and retain professional quality results. I now use CS5.5 and edited my first ever HD project earlier this year. I brought it into Encore and not only were the quality results really bad but it took FOREVER to render. I mean it took all night for this thing to render. I went to bed and woke up and it’s still rendering.
I found this method online and you will not be disappointed. The process looks intimidating and a pain but it is many times quicker than letting Adobe do the work. The quality results will be of professional quality.
https://www.precomposed.com/blog/2009/07/hd-to-sd-dvd-best-methods/
Here’s a companion article
https://www.precomposed.com/blog/2010/10/hd-to-sd-dvd-cs5-revisited/
Also – Jeff Bellune has a video guiding you through this process
https://bellunevideo.com/tutdetail.php?tutid=12
Again – it will look like a big mess to perform the steps – but after doing it a few times it becomes second nature.
David