Throwing the nock to the left - you mean how the arrow/nock is positioned once it hits the target? That wouldn't be the best indicator of bad arrow flight IMO.
Don't have my notebook with me and haven't done much tuning lately but from what I recall with bare shaft tuning you don't worry so much about the arrow being straight on impact but rather where the unfletched arrow impacts versus the fletched arrow. If your bare shaft is hitting relatively close to your fletched arrow at 15-20 yards you should be pretty good.
Shooting through paper with a fletched arrow is another tuning option that will tell you if you're arrow is porpoising or fish tailing bad after leaving the bow.