How to uprez DV

I am cutting a doc that has interviews at 1080, and archival footage mostly shot miniDV, some 720. I don't have access to the tapes. People donated the footage 5 years ago, so they are files. I am using a 720 timeline, thinking this was sort of midway…and it allows me to reframe the interviews.
(up to date ElCapitan, and FCPX, BTW)

Should I do anything more than optimize the DV to ProRes? Is there a good way to increase the frame size?
I am generally 'fill'ing the frame rather than leaving the pillar boxes, and I am generally pleased and surprised that the sequences look really good when watched on our TV (Vimeo>AppleTV).
I don't have experience with mixed formats, so want the end result to be the best rez possible. this is an indedoc, will go to film fests and maybe local TV, college distribution; nothing blockbuster about it.
So: does timeline at 720 make sense?
Is importing and optimizing all I can do for the DV?
Who has an opinion on fill frame vs pillar boxed?

Thanks all!

You might want to check out Red Giant' Instant 4K' - the previous version was called 'Instant HD' and is part of the Shooter Suite.
"Red Giant Instant 4K quickly upconverts your video into a variety of high resolution formats with outstanding results. Its intelligent algorithms generate new pixels to match the dimensions of the desired resolution, then adds sharpening and anti-aliasing to preserve the image details."
There may also be alternative up rezzing solutions by other manufacturers but this is the one that immediatley springs to mind.

Gretta wrote: I am cutting a doc that has interviews at 1080, and archival footage mostly shot miniDV, some 720. I don't have access to the tapes. People donated the footage 5 years ago, so they are files. I am using a 720 timeline, thinking this was sort of midway…and it allows me to reframe the interviews....

DV can be either interlaced or progressive. If it's progressive you have nothing to worry about. If interlaced, you want it optimally de-interlaced otherwise it will look very poor during horizontal movement.

Larry Jordan has an article about deinterlacing in FCPX: larryjordan.com/articles/fcp-x-add-an-in...rogressive-timeline/

There are many deinterlacing algorithms. I don't know which one FCPX uses.