........Toward the Farrs ... the boat will probably make it home before you do.
(Farr 36 ODR = PHRF 9
How about more like, finish before you start the race, if they do a fat boats first, slow last! I did an 18 miler awhile ago, I was the last start, 50 min after multi's, 45min after the Melges 32 bunch, they were all 1/2 -3/4 of the way towards the finish with a 4 mile upwind, then 12 mile down wind in 15-25 knots. They could hold full sail up, doing 7-10, downwind 15, I'm lucky to do 7-8 downwind with my 30' fin keeler that rates 169 ave in the US< 192 local, but we have upped all ratings 10% across the board. I was not even at the first mark when the fast boats were finishing, as the last two miles to the north buoy, the wind shifted to the north, then all down wind to the finish which had the S to N shift in the middle of the sound.......NOT FUN! Now I know why I like reverse starts!
Other factors, keel depth, rig height, more luff, better upwind, less less, more boom, better reach to down wind to a degree. SA to disp, the boats you are looking at are in the 15 or 16-1 range, Melges 32 mid 20to 30-1 for upwind, and 60-1 for down wind along with planing hull forms.
many many items can make or break a rig.