##### No single handicap formula will 100% capture all boats in all conditions, so inevitably ways to tweak formulae will be sought. There are several approaches to this, but care must be taken not to damage the statistical integrity of the formula. For example, it is inappropriate to replace LWL (waterline length) with some other definition of length without a re-assessment of the model coefficients. I will shortly publish an article on model variation, with particular reference to Model 10A (see Article 2.5).