And now you see the problem with the older Nacra one design class rules. They don't publish sail area or measurement rules (check the F18 rules for an example of what I'm talking about). This is a problem when actually checking if a boat conforms to the rules (it's easy to peel a sticker and put it on a non class legal sail). It also hampers sail development, and makes life difficult when the builder drops support.

For example, the N20 with Glaser sails is a much faster boat than the EP version in a majority of conditions one actually wants to sail in. Not sure if the performance sails for the boat are on par, I heard the main cut was a bit off and more to the euro spec (smaller sail plan overall) than the North American spec. I haven't seen the sails myself so that is just hearsay but measure twice cut once applies here.

5.2 is totally different, your best bet is it measure the newest known class legal sail and go from there. Also recommend looking at SCHRS, it may handle your discrepancies a bit more cleanly than Portsmouth.