I've done both instinctive & gap with my arrow. I too am a right handed shooter but left eye dominate. I find shooting 3 under & using the tip of my arrow gapped at the bullseye no matter the range to 40yds helps me with accuracy! At 20yds I'm 3" under spot to hit, 1" under at 25yds & so on. Of course all arrows are cut the exact same length for best accuracy! I still shoot instinctive now & then but prefer gapping!
I shoot instinctive out to 25 yds. After that Use the GAP aiming method. I shoot split finger and and the GAP aiming took a little time to get right. Once you get it figured out it is really easy, kinda like shooting with pins.