Don,
Are you sure about setting the DV-NTSC timeline to Lower Field First? Every tutorial I have read regarding moving EX footage to an SD timeline says to set the field order to “None.” This includes articles by Larry Jordan, Ken Stone and Doug Jensen. Or, does that just apply to progressive footage? None of them made the distinction.
I think what you suggest accomplishes the same thing as exporting a self-contained clip with the correct properties, which has been my solution…..still not very elegant, especially if you have a lot of clips.