I switched from righty to lefty because of a rotator injury, about 20 years ago. The biggest thing you must work on is your timing. To this day, I struggle with that part of the switch. I encourage you to use a 14 or 15lb. ball. I found that medium aggressive pearlized balls worked best for me. I also encourage you to try targeting a spot about 12-18 inches in front of the foul line ala Wes Mallot. It made everything much easier for me. Make sure you keep your game as simple as possible and try to keep your hook to a manageable size. I started with a very small break and now have a hook that would be considered average in size. This is not an easy thing to do. I applaud you averaging 165 in your first season as a lefty. I didn't make that until my third. Today, I average in the 190s and am happy with that. As far as the 7 pin, when I shoot it, I line up ten boards right of center. I do not stand on the extreme right side of the approach. Targeting the 10 board on the left side of the lane near the foul line, I throw the ball on a line from there straight at the 7 pin. The bowlers in my league comment frequently about how accurate I am on the 7 pin.
According to those whom I've bowled with and have seen me left and right handed, I'm smoother as a lefty, but have a slower ball speed. I hope you can have a lot of success with your change. It's not easy and (for me) it is something I always have to keep working at. I have shot higher series as as lefty and did throw a 300 open bowling. I'm glad you decided to switch because if you're like me, I just couldn't quit the game I love. Good luck and don't be afraid to contact me me any questions you might have.