I winterized mine by putting Sta-bil in the tank (proper quantity for a full tank), then completely filled the tank. Once per month I started the bike for 10-15 min, and even in the coldest part of winter, there were no problems. I did not drain the carbs, use a battery tender, or put the engine under load.
It started this spring without any trouble and it's running perfectly right now. Keeping the fluids periodically running through the system and charging the battery at idle worked well for this bike, and the last bike.