Paul,
The 141 rating by YRALIS would be with a 153% genoa and a spin pole length = J. The OD class is a 163 and J+1, so a OD boat would have to rate 135. The difference between the two setups (I think) is the crew weight limit (1400 or 1260) and if you have to sail with OD sails and gear or not. Someone with a YRALIS J-30 ODR rating certificate would have to answer that.