The only reason to shoot SD is if you need to deliver a miniDV tape in SD (DV) format. I’ve done gigs where I was just asked to shoot something because I was local and send a tape to an editor who expected a DV tape. In that case, it’s nice that my Sony Z1U can shoot DV, DVCAM, and HDV. But for myself, I never shoot SD anymore.

~jr

I can see why but if you wanted the absolute best quality - you could shoot it in HDV - crop it to SD and then Print to Tape - but that would be many extra steps I'm not sure I would want to do - unless it was for myself.

One extra step. Not many.
And if you want to stay widescreen, which is the smarter thing to do, then it's zero extra steps.

So I think I found my major problem.

I had been editing HDV on a NTSC Widescreen Timeline.

So correction (1), change my timeline to match what my footage was shot in, HDV60i.

Now when I go to render as a DVD are people seeing better results with:
NTSC DVD Widescreen (default to 30i)
NTSC DVD Widescreen 24p
NTSC DVD Widescreen (Custom to Progressive 30p)