Cutting through your notch whether you're bore cutting or making a conventional notch and backcut is risky business. Once it's moving, it has no hinge to work with and could fall practically anywhere - most likely where it's lean is and can bounce off other trees and objects.
So, leaving your hinge is quintessential, at least for the first 150,000 trees that you cut, so I've been told. Beyond that you're old enough that you will probably die first from other causes.
Like other people have said, if you think it's going to barberchair, bore cut. If you feel comfortable doing it and have had good results, take out the center of the hinge or cut the sides of the hinge. It's all about the hinge! I don't have all the experience, but there are a few simple rules here.
Like clearance mentioned, your escape paths should be away from the tree's direction off fall and not directly behind the tree. If it barberchairs, the wood can/will kick up with a lot of force, possibly taking you out or someone who thinks they're helping you.