From the IQ Foil class website - looks like a good initiative for inclusive and fair racing at a local level rather than limiting to a strict one design rule.

www.iqfoilclass.org/RulesAndRegulations0005v01.htm

iQFOiL Open - 2020 Equipment Rules

The class will invite organisers to include an iQFOiL Open division in their 2020 events:

Board - one board
Any World Sailing Registered Formula board (ie max width 100.5cm)

Foil - one foil
Any foil defined as - 1 mast, 2 fuselage, 1 front and 1 back wing
Each fuselage of a different length - maximum 115cm

Front Wing: 900sq.cm | Tail Wing: 255sq.cm | Mast: 100cm maximum

Fin - one fin
Any fin each of different size for men and women
Men - 68 cm Women - 66 cm

Sail - one sail
Any sail each of a different size for men and women
Men - 9.0 sqm Women - 8.0 sqm

Mast/boom - one mast, one boom