Let me be sure what you mean by RIGHT of thumb. If you're looking down at the ball with the fingers up and the thumb down, that means the MB is the strong position for a right hander, and consequently the ball was drilled for a righty.
For a lefty (as in yourself) the MB is in the weak position, meaning that if you keep that drill pattern, the reaction is most likely going to puke. You're almost certainly looking at a full plug and re-drill for the ball to work acceptably.
On the other hand, if you're looking down on the ball with the thumb up and the finders down, the MB is in the strong position for a left hander, and you have a drill that will probably work well. I'd guess that 90% of asymmetric drills place the pin above fingers between the ring and center grip line with the MB in the strong position. Your PAP will determine optimum placement based on what you want to achieve.
For me, that drill provides length with some backend pop. It's a very safe pattern that most bowlers can throw with success.