It seems to me after having tried every option that the only way to preview interlaced footage properly in the TV set using the secondary monitor preview module in Vegas is to make proxies in mxf (or mpeg2, but mxf seems to be the easiest format to edit in Vegas) at 720p in 59.94, pretty much the same format that ABC and FOX use. Making proxies in that format, then setting the project to the same exact format, and setting the output of the second display to 60p (even if it's 1080p) offers a preview that looks the same, at least motion-wise, to the original, since Vegas can't display interlaced footage properly in the secondary monitor.

My question is, will that bring me some added trouble when I switch the project back to 1080i and the proxy files to the original AVCHD files? For one, I know that if I made any titles while working at 720p, I will have to go one by one to set them to 1080, otheriwse Vegas will keep them at 720 and scale them to 1080, which will make them look not too good. But I'm willing to do that, because I don't think I would have a ton of titles to go through. But my concern is the frame rate. All the cuts, transitions, velocity envelopes if any, and keyframing of filters and pan events, will Vegas do a good job of translating all that to 29.97 upper field from 59.94 progressive? I have to run some tests on that, but my time is scarce, so I thought I would ask here first.