If you have really light wind days, a 134-140'ish drifter/reacher with 1.5oz nylon spin cloth could be a good sail to have in repatore too. Here in the NW we get some summer eve races that includes a max wind to 5 maybe 6 knots if lucky. So even those with the lighter Carbon 155's have problems in these winds, where those with the nylon jibs will go forward.
Otherwise, a good dacron main or a dac/mylar would be good, as would the BEST quality Genoa you can afford too. Go fo teh 155 and the few seconds you lose, probably 6 you will gain more than that in real time at the end of the day. I did getting a carbon 155 last month in the few times I Have been out so far over the 135 I had/still have but sitting in the garage at home.
A folding prop will also net you more than the 6 secs you lose going with one of them vs a fixed also as mentioned.
She drives me boat,
I drives me dinghy!