Haven't learned slap technique yet. I will be taking lessons for that soon. For preliminary studies I am using my thumb doing up & down strokes trying to match the timbre of both up and down. Not easy. Lately I've been playing with GHS brights, they are versatile, combining the wallop of a hex core, & growl of a round core DR. Jesus, after 12 minutes or so my thumb hurts. Looks like I will go back to DRs, just to take some stress off the thumb. How do others do it?