Probably the only way a weight change could be done would be incrimentaly.

Do it a pound a year down to whatever number the class would like to see. Most are built 10lbs underweight right now anyway aren't they? By the time the minimum has dropped that ten pounds the overweight boats aren't being raced any longer anyway. It'd give plenty of time for technology and engineering to keep up.

And just think, in a short 396 years, the boats would be down to zero......