Use one Paraliminal with one goal for best and most solid results.
If you use butt the sleep learning tracks I suggest you use use the most appropriate ones for your one goal and make sure that you're able to answer the questions in the booklet to keep them relevent.
I just use one sleep learning track and repeat it for about 45 minutes to perhaps an hour. Check the results and then decide if I need to use another Paraliminal. I guess I just like seeing results rather than wondering if I giving in to my impatience worked.
Alex