I am the Secretary of the Narrganasett Bay S Class fleet and owner of FIREFLY, hull #956. Several of the active boats have reef points, and I know some S boats in the Quissett fleet have reef points. Reef points on a sail are not preferred when racing, although I am not sure it would affect performance much if the sail is otherwise well cut. If conditions demand a reefed sail, racing should be reconsidered, if for no other reason than the cost of a new mast. In the 2010 Museum of Yachting regatta, four S boats raced in a steady 25-30 kt SW wind with no reefs. PIRATE was the only S boat to set a spinnaker. SURPRISE broke her boom. ARGUMENT struggled with a small crew. FIREFLY won the race. In contrast, the 2012 Leukemia Cup Regatta was held in a gusty 25 kt wind. Three S boats (SURPRISE, WISTFUL, SHONA) attempted to race without reefs, and all of them withdrew before the race started because they felt conditions were not safe.
The heavy weather sails depicted on DILEMMA in Herreshoff of Bristol p. 155 shows a vertical seamed batten-less storm sail set above the regular full size sail that remains on the boom in its sailcover. The storm sail has a set of reef points as well. This arrangement makes a lot of sense for crusing in heavy air since it would be difficult to reef the mainsail underway. Of interest, DILEMMA is actively sailing in the Larchmont fleet.