You are lighter than the third placed boat at last years nationals. Being heavier only costs you when sub powered, and
That will be us then!
Basically we sail like this...tomorrows forecast in knots is inversely proportional to the quantity of lager and kebabs consumed tonight. So, for example, if the forecast is 5 knots, Tom and I will eat at least 2 kebabs each and probably 10 pints of lager. That way, we can have a lie in nursing our hangovers and say that we need to repair our oscillating flange gasket or whatever we have chosen to pretend we might have broken so we don't need to go sailing in conditions that are better suited to observing the floating about from the bar.
However, if it's 20 knots, it's Horlicks and bedtime as we will want to be on form to kick some windy ass the next day. the only time that this rule is overruled is if the forecast is over 30 knots, in which case we get into competition drinking mode, in the hope that either racing the next day will be binned, or if it's not, we'll still be too pissed from the night before to worry about the whole dying thing and think that a port end flyer might be "a bit of a laugh".
In all seriousness the boats are all so diverse that it's not just like plonking a heavy crew into a one design with the inevitable results...yes you might be a bit slower in the light stuff but you will more than make up for this with decent boathandling and tactics, and you'll go really well in breeze.
Boat setup can help too...my new boat will have another barn-door mainsail and a huge daggerboard and a big T-foil.
Do it!!!!