People who speciaize in operatimg cost estimates are consutants.
Not exactly inexpensive data and information.
You try to get info worth $$$ for free on Pprune...
Typical rates might be US$3,000 per week, or $10,000 per month/30 days, full time.
For that price you get operating costs computed to the nearest penny.
But you need to inform that consultant of full details of intended operations.
"How much is a 747-200F/CF6 per hour" is unsufficient data.
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Happy contrails