my question is, if I want my abs muscle to be bigger should I go with low reps and heavy?

and if I want to be defined abs, should high reps?

My view with Abs, just any other bodypart is that building muscle is building muscle. That said, I train abs with sets of 6 to 15 reps.

I also shoot for an accumulative total rep count of over 40 per workout.

I may do one ab training session with reps of 6-8 which means I need to do about 5 sets (5sets x 8 reps = 40 repas total)