135% vs 150%
D, I''m assuming you are having the boat equipped with headsail roller furling/reefing. And it''s reasonable to assume you will want to be sailing the entire LI Sound season, right? Perhaps April through October? And the way you have positioned your question, it appears you will only equip the boat with a single headsail, at least to begin with?
If all the above is correct, choosing a 150 would optimize your sailing in the summer but at times present too much sail area in the Spring and Fall winds...and when reefing a 150, you''ll be likely to distort the sail''s cloth when reefed in heavier winds, due to its lighter weight. If choosing the 135, she will have less sail area in the middle of the season than you''d like (but be a bit easier to tack & trim), and you''ll no doubt notice lots of MPS/Drifter/Asym Spin-type sails out on the Sound when boats are trying to catch even more of that soft wind.
IOW no one sail isn''t going to meet all your needs. If choosing between those two, I''d opt for the 135, have it built with a luff pad (polypropylene won''t mildew; foam will) so decent shape will be possible when reefing down to 120-110 in size, and then begin writing my letter to Santa early this year.<g>
I''m curious what experienced LI Sound sailors might think. Jeff?