Rigging Wise:
Is there anything you can drop off of the lean side to reduce the weight until the crane is available? Rent a bucket or tow behind lift maybe. You can probably rent a 60' 4wd lift at a regular equipment rental place, or maybe a tow-behind lift.
As many guy lines as possible. I'd think about tensioning each rope then trunk wrapping the standing end of the rope. Then go back to the beginning, and add more tension, as seems reasonable. You will get some feeling for if the tree is gaining support from the ropes.
EXAMPLE. If you tensioned rope #1 to 2000 pounds of force, then tension ropes #2, #3, #4, and #5 to 2000 pounds of force, then go back to #1 and the tension is only 400 pounds of force, then you've gotten somewhere. Rope #2 will probably be lower that the initial 2000 pounds of force, but greater than #1's 400 pounds of force. (Bearing in mind that each rope will stretch/ relax after being tensioned, resulting in a decrease in overall tautness).
Whereas, if you tensioned them as above, but the force on #1 only dropped to 1800 pounds, you might be fighting a losing battle and hoping the crane can come fast.
Seems like you might need two cranes, one to work from and one to carry wood; or one to support the tree, and one to take pieces maybe with you in a lift.
INSURANCE WISE: You might want your liability agent to call the neighbors' homeowner's agent.
What I've seen done to get a written copy of a discussion (not trees and insurance related BTW), is to be on your email account writing down what is being agreed upon as a course of action, and send it to the agents involved, asking them to look it over and email-reply that they received the email.
Email correspondence may be evidence if something goes wrong.
Seems like you are going to find out some of the details of things that we all probably have wondered about. Impending destruction of property---could maybe be saved, but what if...
COVER YOUR *SS!!!!!!
Its not your fault that the tree is leaning over their property. It hasn't fallen in a storm, unexpectedly, so the homeowners have a chance to be safe themselves, and get out precious property from inside, or at least rearrange it to a different part of the house. It would be great to come off as a hero in this situation, but beware the could be lawyers becoming involved.
Has any of the neighbor's property been damaged yet by this tree? If so, their insurance may cover the removal cost, whatever it may be (say 2 crane and a lift) to prevent super expensive destruction. Once property actually gets damaged, I think that the agents will have more latitude to authorize the work. GET THE AUTHORIZATION IN WRITING WITH THE AMOUNT. Allstate tried to reduce an authorized bid by 1/3 after the tree was safely removed, and the roof tarped by us on a Carbondale tornado job.
