I've seen people use Starbrite as a bottom coat before regattas, but I've also heard that waxes are slow. What's the best way to prepare your hull for a big race?
A matter of opinion, of which you are fully entitled. I've sailed F5's before and like the boat. However, you cannot dispute the strength of the Laser Class and the many opportunities for competitive sailing to be had through club, regional, national and international events. F5 as a class offers too few competitive sailing opportunities with your F5 peers.