You are correct that the overweight status of the SC18 and the N18Sq does not affect their being class legal. I recall a reading a review of the SC18 when it was produced and the Main stock supplied main was too large for an 18 Square. Easy to fix with a legal sized main....

I would love to come play with some other boats, but chronically short handed at work and working 2 out of 3 weekends these days. Time off is too limited. Sad to admit, but I haven't been out sailing in over 2 years....
Still trying to get a life.

Steve