Done a fare amount of crane work ranging from ten ton to 110 ton. I always use rigging slings unless the wood is just to big or the operator wants cable.But 90 percent of the time, slings. Much easier to handle and for balancing.
Communication between you and the operator is key before the climber even enters the tree. 2 ways are great for this. Hand sigs, don't always work unless you have a spotter to relay or a clear view of the operator. All those hand sigs. your suppose to use, never come into play if it's just you and the operator.It becomes one handed signals because your usually hanging on with the other.
Where you place the slings,cable on the branch or trunk and where you make the cut or how, can make a huge difference in how it lifts and reacts when coming off. Some operators like to lift the branches and some will pre tention and let you ease the weight into the boom. I don't care for that style , but at times it's necessary. Once you get approximate weights and radius down, the rest becomes a piece of cake. For the most part anyway.
I very seldom use a spotter to set the boom over the load unless I can't see. I will generally do it my self as long as I'm in visual or voice communication with the operator. Reason, I like to set the cable angle to my liking per load. One of the last crane jobs I did on a big black walnut, the operator was good enough to place the cable almost exactly where I wanted it and set the angle if need be... Saved a lot of time.
Even though cranes save huge amounts of time and delete hazards, there are still many things that can go wrong to which I probably don't have to mention all of them. i.e.... The last job I did were 11 cotton woods some fairly large some tall and skinny. 25 ton crane and he likes to use chokers. I was addimit about using slings instead. He asked why. I said because Cotton wood is brittle soft and when taking the tops cable may pinch enough to sheer the tops off and there goes the load. He had know problem with slings....
Have fun ! it's a great experience...
i.e