[strictlypersonl]

First, take Pat's advice and check the fuse to make sure you've got an actual working charging system.

For the amount you're going to use the lights, I wouldn't run their current through the ammeter at all. Take the power directly from the battery, use a relay to switch the power from the dash switch.

Unless you're going to run night races, I wouldn't bother to put in a larger alternator. You're not going to need the big lights under 50 mph, at which point you won't be using the radiator fan at the same time. Keep things simple.