i have dug out my old iF20 rules and here are the basics;

Hulls without rudders 6.12m max
beam 2.6m
min weight of platform 140kg
min weight ready to sail 190kg
top of front beam to top mast black band 9.75m
lightest crew weight without correctors 165kg
main area 18m2
jib area 4.85m2
spinny area 25m2
[light weight crews carry smaller jib and spinny]
carbon allowed in mast, rudders and daggers only

hope that this is of interest

Paul