Rated LPG makes a BIG difference in PHRF racing. (especially for boats of moderate disp.)
Every district has a different 'datum' for the standard rating.
Many start from 155% of LP.
So it would be something like the following: (rating based on LARGEST sail in your inventory)
155% no change std rating
etc.......... (some other factors I've left out)
In a long skinny boat, like this one, with a small foretriangle to begin with, overlap means speed upwind.
You want to at least think this through before you send big money on a headsail.
(I'm not selling sails.).
Just something to consider.
I bought a racing jib three or four years back. We went with kevlar, and did much better racing than we had with dacron. And although it is startingto show its age, it has held its shape much better than our last dacron jib. we do not use it cruising.
As to size, you should consider the prevailing conditions in your area. Because we sail in Narragansett Bay (where the winds are pretty consistent), we went for a 145 and got the three point PHRF credit (we think this worked out well for us). If you are in the Long Island Sound or an area where the winds are generally lighter, you may want to go for the full 155.