One of the hardest things a 9 Ball player has to learn about One Pocket: forget about making every shot. Getting a ball close to your pocket and leaving your opponent safe is a skill.
The fastest way to learn One Pocket is to play partners with coaching allowed. Make sure each side has one good player. Don't take all day to make a shot selection or it gets boring for everyone and don't coach on each shot.
It would help if you take a photo of some shots to practice them later.
Just to put this in perspective based on your questions. I am 83 and trying to maintain or better a 585 Fargo by playing in 2 eight ball leagues a week using a parallel aiming system. One pocket is my favorite game but I do not get a chance to play it much. My custom cue is Alex Brick/John...
If you are right handed it sounds like you may be pulling your elbow in slightly in toward your body giving you unintended right English. Did your instructor video you from behind? Something is moving the cue to the left.
If your normal bridge is 12" and your shaft has a pivot point of 12". What would be the effect when a player decides to get an LD 18" pivot point shaft and still maintain his 12" bridge length? What compensation would be needed?
This makes me think the tip shaping devices that puncture deeper in to the tip may cause crevices that will hold chalk longer and cause more frequent skids. Just a thought.