First a big shout-out to Andrew for such a great DIY. I thought I'd show my experience to add to the knowledge base.
First, on the ziptie... my carrier was cracked, but the casting wasn't missing any of the part holding the hinge pin, so I put the clasp of the tie on the other side where there was more room. I then used a couple old decking screws to thread under the tie to shim it. This worked nicely, as I was able to screw the screws into place and really tighten up the tie. You have to screw the screws in from opposite directions so they can mesh properly.
Second, on the cable... there IS a way to adjust the cable a little. The end with the ball socket has a black cap holding the socket in place. Remove that and you can see that the cable barrel and socket appear to be threaded together. They actually aren't, but rather just have concentric grooves that mesh. You can carefully pop the socket off pushing the barrel out sideways through the gap and reposition it deeper over the barrel. I didn't take a "before" picture, but on mine, the barrel was about flush with the end of the socket and now it is maybe 6-8 mm lower in the socket.
It's not a lot of adjustment, but it did help mine release the door with slightly less lift than before.
Hope this helps someone else.
AM.