Whatever you read about not sailing a Hobie 16 over 280 is garbage. If racing (which you didn't mention), minimum weight is 285, ideal weight is around 300 (+/- 15 or 20 depending on skill). Although rare, some folks have done well at significantly higher weight.

Sailing for fun has no such restriction. We commonly fun sail with three adults on Hobie 16s.

Having said that, the best way to quickly improve your sailing skills is to race and attend clinics. The best advice for that is to buy a boat with a large fleet nearby.

Hope this helps.

Mike