I fell trees proffessionaly when i was younger, but only for about 6 months, before i started bucking, so i am by no means an expert, or claim to be one, but i did learn that even with the best laid plans, things don't always work out. If you 'need' a tree to turn against it's lean in order to miss something important, expensive, or dangerous, don't depend on a couple inches of holding wood to make it happen. My son is an arborist, and they don't hesitate to put a rope in any tree that can reach anything, and if they're not 100% sure they can pull it, he'll climb it and piece it down. They don't leave anything to chance, and he and is crew are all good fallers. A bit of rot on the side of your hinge that you want to steer by is all it takes for a tree to break off, then it's going where ever it wants, so just be sure to plan the job properly, don't leave anything to chance, or you will get bit eventually!