I'm afraid I didn't actually complete any mixing - I just started testing the process as outlined by Ady in post 26.
The capturing of the separate channels (via WinDVD and Sound Forge) seemed to work well, but when I tried syncing the mix to a PAL > NTSC converted GOUT video, it just didn't marry up properly.
Once I've laid my hands on an NTSC GOUT I should be able to do a little better!