Rather than work on opinions, I have emailed the PHRF Southeast Florida Chief Measurer and asked the following quoted below. I will post the reply I receive. I would like to ask folks in other PHRF districts to send a similar email to their PHRF rating committees and ask for a response.

Quote
The J/30 Class is discussing the possibility of making a 0.5 ounce spinnaker a one design sail under its class rules. Currently the class requires a 0.75 ounce spinnaker.

Would you please comment on whether PHRF-SEF would change the rating for the J/30 if the class allowed a 0.5 ounce spinnaker that is the same size as the class 0.75 ounce spinnaker? I can state that PHRF-NE and PHRF-LIS (YRALIS) have both indicated that there would be no change in the rating.

You may read the discussion on our J/30 Forum at this link:
https://j30.us/ubbthreads/ubbthreads.php/topics/15844/0_5_oz_Spinnaker.html#Post15844