Well, if it wasn't scary before, it sure as heck should be now! My suggestion is stop, now, and go find someone who is very experienced at felling dangerous trees, to assist, and who would hopefully have a saw with a longer bar. You may need to take it all down now, but you are not going to pull that thing off of the stump as is, in the picture.
I may be confused because I thought the goal at this point was to take the side limb off but maybe the latest cut was the base of the whole tree. Just be careful none the less.
No I am not a professional by any means so take what I say with a grain of salt. In your picture I don't see a face cut if you do not have a face cut you have no directional control it is going to go backwards, you didn't say what kind of tractor you are using but without a face cut it is going to take a massive tractor to pull it the direction you want. If you're hooked to it with say a 60 horsepower or so tractor when it goes backwards it will take the tractor right with it. If you can still get a face cut in it and wedge the heck out of the back of it you still might be able to get it to fall the direction you want but I cannot say so without being there and just looking at pictures just be very sure you have a very clear 360 path to get out of the way and watch the limbs and the tree like a hawk when you are working on it
I'd use a pole saw to piece out the top as much as possible. From a distance. I'd rather be pulling out 15 modest hung limbs than one giant one. But with that latest cut, I would be dammed careful. Could swing who knows what way.
