For many years I sailed at a club that used a "back calculated " handicap system to ascertain, What they considered was the best way to judge the "best sailor" in a very mixed fleet (fleets of various cats as well as multiple mono hulls). They used this system over the duration of the racing season as well as for regattas of four or more races.
The way it worked was that the first race was sailed and from the finishing times of all boats their "handicap" for the next race was calculated on the basis of the times needed individually for all the boats to have finished equal first (on handicap). This "handicap was then applied for the second race and the resulting positions counted for the overall regatta (the first race was used as the starting point and didn't count in the overall results). Similarly the same "back calculated" handicap system would then be applied for the resulting times of the second race ie their handicaps were adjusted as if they would all have finished "equal" at the finish (on handicap) and their "new" handicap would then be applied to the third race. This "handicapping would continue for the duration of the regatta/ season.
Very accurate and fair comparisons between different boats, sailors, and sailing skills were obtained from this system and it is the only system that I have seen where there was never any argument between competitors about the final results being "unfairly" influenced by, conditions, quality of respective boats, difference in speed and/or performance of boat, weights, etc.
It was a system that automatically took into account ALL the variations between different boats, speed, weights etc, and put every one on "a level playing field". At times different sailors tried to "rort" the system by "sand bagging" for one or more races to greatly improve their handicap, but in so doing they may have been able to win ONE race as a result but with their results from their "sand bagged" race/s and the considerable resulting handicap penalty resuling from their erraticly improved "winning" race, they always suffered appropriately. The best way to sail under this system was to always sail "to your best" for the first race , and then try to sail every following race with improvement ie sailing up to and better than your previous race's handicap (ie consistency). The calculations necesarry to incorporate this system were simple and the results were always available within approx' 30 minutes after the final boat crossed the finish line.
It is a system that proved itself over a long period of time and required no measuring, no boat formulations, no class yardsticks etc, all a sailor had to do was to turn up with their boat and they knew that for any regatta or series at that club, they could race on an equal footing with ANY other class of boat and sailor. It just worked to perfection for fleet numbers from as little as 12 boats up to regattas with numbers into the hundreds. OD, one off's or even for a "bath tub" with sails made no difference, the system worked and worked well.
This is the primary system used to calculate the "yardstick" for different classes of boats, the difference at this club was that they used it as an ongoing "living" handicap system that was continuously "updated" and didn't stagnate (like a yardstick can) for the entire season/s and unlike a yardstick, would not loose it relevence to the average sailors actually competing week in week out.