Beware of CO's with little or no experience working tree removals.
Never make a pick anywhere close to the crane's capacity at any given distance or angle, be extremely conservative in the size n weight of your picks until you've got a lot more crane jobs under your belt.
Learn your crane hand signals.
Get an integrated hardhat with two way radio communications, like the Peltor Pro Comm.
Get a green log weight chart calculator that'll give you an accurate estimate of how much a twenty foot long 30 inch Diameter red oak green log weighs. Answer? 6180 lbs.
The best advice I can give you's to make sure the CO's got lots of experience doing tree removals.
jomoco