What is the best way to drain the fuel tank.

Wide open throttle for around 45 minutes

1. Two wires, preferably with alligator clips on the ends. Hook one to ground, the other to the hot [pump] wire so it's a direct feed to run the pump. Charge the battery after draining.
2. Remove connector(s) and fuel line. With gas cap off, flip tank and capture the gas in a 5 gallon bucket. Lay tank back in position, prop it accordingly, cycle key to remove remaining gas.
3. Take a ride with a loop about 150 miles... is with a full tank mind you. Other mileage loops vary with what is left in the tank.
4. "Wide open throttle for around 45 minutes" ... depending on what is left starting out in the tank vs minutes.

Wide open throttle for around 45 minutes

I just use a squeeze ball syphon I bought at Advance Auto. It takes a long time but it's safe. A bit of a PITA to keep the hose from curling back up but you can get most out in about 25 minutes. Try t0 not scrape the hose on the sharp edge of the splash guard. You will need to reposition the hose many times.