[hypothetical] Now if I were to come up with a CTSW with a MTOW of 600 kg?
Not sure if this is possible for this particular airframe, but AIUI several CZ-made airframes are available with MTOW of either 450/472,5 kg or 600 kg.
More generally, I think one cannot speak of "THE" CTSW but ought rather to consider individual airframes, each with their own paperwork.