Sounds like a Barbie doll: “math class is tough”. Helicopter flying is tough, you could be overgross and fly away, or under and crash - there are a lot more variables than just weight. Try refine the mission to something like “I want to carry 1000 pounds ”x” distance, and the t/o landing areas are”xxx”. 6 anorexic strippers weigh less than 3 NFL linemen. More fuel than you need for the job is granny gas.