I find myself using medium and large ring and ring retrievable slings most frequently. Hands down. I've got a 3 foot and a 6 foot version and I use them both about equally. Another benefit is I'd you get a triple thimble spliced up in a loop you can attach it like a prussik to get remotely...
Just a couple of things to add to your thinking...
We in the arb industry live in a much more elastic world than other rope disciplines. Our trees bend and flex, unlike structural steel or rock faces, so where other industries need rope stretch, we can get away with dynamicaly loading our...
I'll second using omni blocks on ultra slings as my redirect. Usually a triple thimble as my main rigging and friction point, never had wear even close to that...
HOWEVER I have seen the omni block get pinned under load and not swivel in line with the rope causing the rope to run on the side...
I work away one if the largest and more progressively minded companies in town. Or of the 30 or so climbing capable employees (varying skill levels) 1/3 or so are still on a closed loop or split tail, 1/3 are on some hitch based system, and the last 1/3 are on mechanicals (zigzag or spider...
1 yes, it's a regular practice of mine, and no pulling it through for ground help isn't too bad.
2 not quite, I'll have to take a picture tomorrow to illustrate.
Having owned or used everything in your list plus a rigging wrench I would like to say that I own two thimbles because they're phenomenal. One long one on a ultra sling, and one on a short loopie style sling I can girth hitch to a dead eye rigging ring to make a remotely retrievable device...
Probably, but then there's no redundancy, and it might not load the rings evenly. So both ropes would need to follow the same path through the tree instead of having one redirected. Only way to know would be to try it
If you do that, a pair of alpine tied midline should be fine, one for each ring and you get 2 legs of rope to work off. Still only counts as one point of attachment though
I have one I made that's about 4 feet long and it's too short for a lot of things, and I find 8+ to be a bit on the long side for most things. Next one I make is going to be around 6 feet long
If we're talking about side loading in the sense of a pinto cinch canopy anchor, I've heard it's a no go at dmm... if you're looking for one that seems to be ok, the art cocoon, with a stopper gate and a trapeze is ok (you've got to look far and wide for the parts, and dig really deep into the...
Limb size isn't as much if an issue with the hook.. just flip a bight if rope so the hook hangs low, flip another bight, catch the hook with the rope, cinch tight. Take a bit if practice, but once mastered is ready
Or flip enough rope through you catch another branch that's smaller below the...
West Marine has elastic dock lines by the foot. Can't speak to long term durability for a knee ascender. But as a bungee Esq saw scabbard keeper it lasted on the boom of the bucket for several years before I broke it. Should have enough stretch for you as well