@Trackball
as a former rock climber, I see a real problem (no pun here) with the decent regulator/brake assembly. Not real happy with the bos'un chair approach, but can see some pluses for use in an emergency....
The attachment point of any system should employ a
locking carabiner.
Nearly as good (or better IMO) would be the 'correct' amount of 11mm kernmantle nylon rope (or 9mm Spectra rope) in a throw bag , a climbing harness - this to secure your ass to the rope and a 'figure 8' descender device - almost universally used by fire brigades here in the US.
Thus, attach the locking karibiner to your eyebolt, climb into harness, attach descender device and bail out.
Videos for each
Aluminum locking carabiners are strong and secure enough for almost all purposes, from climbing to hanging hammocks.
www.rollingstone.com
A screw karabiner avoids issues with ice/snow or twisting unlocking the system. These were all I ever owned.
climbing harness - these will hold you even if you should tip 'upside down'
Figure 8 descender
Using a throw bag for rope
much of what you wish to do is a daily task for tree care specialists and in common use for mountaineering/ The setup I have listed does require some training/ and recurring practice -
as would any self-rescue system.
Using just this equipment I have listed, I have repelled down a 140 ft cliff face,
upside down, to demonstrate just how well a harness works in holding a person in any orientation. Given this will most likely be used in the dark, a strong flashlight to stay in the equipment bag is a must.
If
small children are involved (<20kg) - they may be strapped to an adult.
Here, practice is mandatory.
Good luck, and good that you are giving this serious thought.
.