rumination
Migratory Hippie Arbolist
Brian, your setup rocks.
treevet, it's an oak. We call them laurel oaks here.
Also, make note in the first picture how the carabiners are positioned. They are laying flat on the log and the orientation is such that the load will be on the spine of the carabiner, not on the gate side. In the second picture you can see that the load is squarely on the long axis of the carabiner.
And Justin is correct. I've started using a similar method when I have to rig stuff when climbing. If it's just one or two limbs I can rig them off themselves with loop runners then piece them out and throw them down faster than taking all the time necessary to get a lowering line sent up and then taking up the groundman's time to rope the limbs out.
I've never one handed a saw in my life, Burnham. At least not that I'll admit.
I have different length slings so I can usually grab one that's the right length. I can also connect two together and/or take two wraps on the limb. When there's no fork or nub big enough to prevent slipping, I'll usually wrap the rope twice. On that particular cut there's a nub that you can see plus there was another larger nub on the back side. I'm quite anal about making sure the rigging won't slip. That double braid polyester rope also tends to grab the bark a little, sort of like velcro but not that much.
I appreciate your concern though, and those are good observations to mention for someone who might want to imitate this type of rigging. It's very easy to do it wrong and have it fail if you're not thinking through every link in the chain.