Felling a tree in the exact spot you planned has to be a rewarding experience. There is so much that could go wrong without the understanding/experience of how trees react. I understand the concept but in a tight spot I would get someone like this guy (1st 3 mins) to take care of it.
Most of the time it needs to cut softwood because when you cut too much hardwood you cut the notch from above for gravity assist because hardwood is harder/harder. I should have used more than 1 wedge and it's better to use a longer rod but this 1 was fine too. The hinge was pretty wide, but with softwood you can get around that, but with hardwood you often can't get away with it because the hinge can be what we call a "barber chair" if the wood isn't hollow.