i presume you know the technique well..
If so , do what sounds good to you, but what ever you do , DONT slap at a thousand miles an hour where the music is lost and its a platform for your incredible agility. ( i hate those You Tube idiots)....i dont know what music you want to write a slap line to, but generally (IMHO) less is more..
A great way is to work out a simple bass line that fits the song fingerstyle, then thumb the same bass line, adding pops, etc when you think its sound ok...
At the end of the day, Slap 'technique' is just that..it shouldnt rule the sound..again IMHO...