The rule of thumb is that 10-15% of the total
weight of the trailer should be on the tongue. So, a 1200 lb trailer should have 120-180 lbs on the tongue. Less than then, and the trailer will tend to sway and fishtail, and get pretty dangerous, especially with front-wheel-drive. You can go somewhat heavier if your tow vehicle can handle it (ie, rear-wheel-drive and heavy enough hitch/suspension), although the trailer may start to "push" you through turns, which isn't cool.