Original media at HDV 1440x1080 29.97i - conversion to 1920x1080 29.97p, or even 4K?

I'm working on a feature doc shot in HDV. The original format is HDV = 1440X1080 29.97i ... which displays on the FCPX timeline as the standard HD 1920x1080.

I'll want the master to be HD 1920x1080 29.97p ... or possibly 4K (cinema) depending on if additional shooting is done.

What's the best way to work?

1. dump the 1440x1080 29.97i on an HD 1920x1080 29.97p timeline - let FCPX auto-deinterlace?
2. dump the 1440x1080 29.97i on an HD 1920x1080 29.97p timeline and use plugin to deinterlace?
3. dump the 1440x1080 29.97i on the same timeline (1440x1080 29.97i) and de-interlace?

I've tried all above variations and as far as I can tell the image looks the same.

I'm going to edit in standard HD 1920x1080 and if 4K media is added, then bump the final cut to a 4K timeline.

I just recently cut an HD film with 4K media ... bumping all to 4K; and I don't know whether I'm crazy but the HD material looks better up-rezzed to 4K. So even if this film is all HD (HDV actually) I'm contemplating bumping it to 4K to get that little bit of extra zest that some FCPX algorithm seems to add in.

Any suggestions? I'm all ears ...

Ben