If you want the audio onto separate tracks from the Tascam I recommend buying two of these (or maybe even more useful, buy 4 x rca > 1/4’’ adapters and 4 standard 1/4’’ cables) and run the audio from the 4 “tape outputs” to all 4 1/4’’ jacks on the saffire. The reason for this is that two runs through the same recording on tape will never be completely in sync.
If you just want your stereo mix then one of the cables will do. The cable you linked will either give you a stereo to mono mixdown or require you to record the tape serveral times to get the tracks separate, not recommended.