Bryan I’ve heard that doing it that way will yield lots of undesirable artifacting.
What I do if I know for a fact that SD will be the only output required
by the client (and they agree as well) is to capture the footage through
the analog component inputs and set our multibridge extreme up to do an anamorphic downconversion.
So we effectively capture in SD in fcp and the multibridge downconverts it just before ingest into fcp. The quality is top notch doing it this way, but because its HDV you also have to capture the audio as analog and there is no batch capturing available. (wish fcp would allow just firewire as deck control and our sound input)