For what it's worth, I am buying new sails for the J/30 I bought last August. Exchanged emails with PHRF NE Measurer. I am going with 163% overlap and J measurement pole. Rating is supposed to be 138 in that config. ie; 144 base less 6 for 163% overlap. In ODR config it would be 135. 144 less 6 for overlap and less 3 for pole penalty.