All the littlies are RG65’s. The RG65 class is a very open rule set and open to experimentation by design, with just a few constraints such as monohul, single rudder and keel, 650 long, max sail area, max mast height – but the rest is for experimentation.
The DF65 is literally the Joysway DF65 yacht only, and to remain “in class” it effectively remains as per out of the box, with the exception of decoration, sails (can be after market), but the rest needs to remain as manufactured.
Hope that helps