Just an update. Shooting with one arrow has been hugely successful. i dunno if it's the break time between shots, the added sense of focus using a single arrow or what but it works. I shoot from different distances (unsure of the exact distance all within 25 yards) each time and shooting purely instinctive I am back in the zone. I also find that I shoot best when I don't think, just draw and shoot. I think not rangefinding will help in the field.
I wouldn't sweat it. I watched the South Cox video and I'm an absolute bow assassin at 5 feet so I've probably been practicing too much for my elk hunt