Better you side rope it than take chances, even busted fences cost time to go get the bits then come back and fix them.
It's important the side line is tensioned and at 90degrees to the notch. Just looking at your pics made me wonder if the side rope stretched a lot or came loose etc but makes sense if you had some slack.
A few things I would have done different is installed it all from the ground, do you have throwbags? The notch, but you know that, kept the cuts level with ground not on an angle like your last pic and the parallel back cut would have been more triangle shaped and wider opposite the lean (pie cut) which leaves more holding wood to prevent hinge failing.
No big deal, was a good tree to test your knowledge on, as they get bigger so does all the rigging but the concepts remain the same.
The video in this thread shows all of this including the offset for lean, parallel to ground cuts etc.
http://www.treeworld.info/f7/trainin...eaner-140.html