It seems like I was able to recover progressive frames entirely so I went ahead and did that. It's encoding to x264 now and I'll up it sometime tonight.
EDIT: I'll hold on to the raw capture for sure but it might be awhile before I get around to testing the pal 3dcf on the 750 since I'd like to finish ld-decoding the laserdiscs that only have analog audio first. When I do though I'll post it in your comb filter thread.