SCHRS uses the4 BOAT weight, the CREW weight and the righting moment of the boat plus crew (Hiking or trapezing) as part of the basis for calculating the rating.

We went thru a big exercise to rate light boats better a couple of years ago that resulted in the A class and F16 rating changing.

Texel and SCHRS generally produce similar performance differences between boats; Texel only uses 2 decimal places in their rating (so giving scope for some "designing to the rule" as you can "gain" 32 seconds buy making the boat rate just above the click over point to the next rating as the rating is rounded to 2 decimals); SCHRS uses 3 decimals.

We do provied a guidance conversion for SCHRS to the RYA Portsmouth rating; I am sure a similar guide could be calculated for US PY.