You might. My experience is with my P19. I spent a lot of time tuning my
genoa, and I found that on my boat with my sails, the best lead position was
forward of the jibsheet cleats, so I just use them. I'd install some
telltales ASAP and just jury-rig your cleats for now (use the stern cleats
or whatever) until you find the lead positions that cause the telltales to
all react together. Once you have this figured out (or at least a ballpark)
it will give you an idea whether the existing cleats will work or if you
need others.
I think both potters are undercanvassed for the conditions many of us sail
in, and adding a genoa greatly enhanced my sailing enjoyment. Go get a
whisker pole too - that will make sailing the genoa downwind a lot of fun. I
have only gone to a smaller headsail once this year, at the race last
tuesday. We were a little overpowered with my genoa. My crew that night and
i are each 200+ pounds so we could have sailed that way using a lot of rail
meat, but since we both had to be on the rail, there was nobody to post
lookout on foredeck, and i can't see around the genoa. I got real spooked in
all the other traffic (starboard tack means the other guy's insurance pays,
but you still get hit) so at the last moment we switched to the lapper.
Other than that and my experiments with my cruising chute, the genoa has
been the only headsail I've run all year. You're gonna enjoy it.