If you're at 10,000 lbs, you'll be in a Part 29 certified helicopter, and you may well have some other limits to worry about before we get to the discussion of how much more lift you get at translation. Pay close attention to the limitations section of your flight manual.
Where are you starting from - a low hover at the height in the flight manual for IGE hovering? Or Out of Ground effect?
And what do you mean by a 'maximum effort takeoff'?
Why do you need to worry about using translational lift to get you off the ground / away from the ground? if you can't hover at the height in the IGE performance chart - should you be attempting to lift that load at all?
Sorry to be so negative, but there is a lot more to the legal aspects of performance than 'suck it and see'.