Why don't you just try climbing by the book once and the next time with your high-speed profile? See how long it takes to get to altitude, what your fuel burn is and how far down range you are when you're level and compare. Your FMS will show you "air miles" flown so a few turns won't make a difference.
Of course weight and temp will vary but we all have flights that depart at similar weight and temp.
Sure, you might have to make an ATC level off here or there but after a few tries you should have your answer. Might not be exact but you will see the trend.