I was trying to be idealistic, because our local fleet did as you are suggesting for 2 years and it doesn't result in a 'fair' rating per SCHRS (see the jib vs. spinnaker area issue above). If your fleet is okay with this, then go for it. I just kindly suggest setting up a fleet SCHRS focal point that can generate ratings for the frankenboats given basic input data for future events. That is what we do locally-I run the ratings as I volunteered, it is fast for me, and my number doesn't change (F18's have been 1.000 for a while now). I will kindly generate numbers for other boats if they can provide the input data, or if I am at an event and not fixing the bottom of my daggerboards, I will help measure. I will see what I can do to become an approved measurer.
Once you do become an "approved measurer" let me know what needs to be done as this is something I may want to do...
With that, the calculator and the other instructions that are online will work as much of the data has already been done... that is some one with a Prindle or Dart 18 shows up with a new square top all I need to do is go to the rating table, plug in the known data, then the new data for the sails (CM & CJ) and get a number.... easy peasy lemon squezzy right?????? Wrong!!!!!!!
The problem I had last year was that some sailors were not able to get the required measurements from the sail makers.. Even with my new sails for the P18 from Whilewind, Chip almost choked when I sent him the chart below noting that he didn't have the time to do this.. In the case of the Dart 18 sailor he noted the Glasser was not able to do this asw well... which was suspect to me, but that is another story..
I am going to try and messure my new sails and will send you the messurements to see if they "jive" with mine..
More to come