i might use a polesaw to 'cheat' as JP reflects, but not with any real pressure on it (like i could muster any!), as i consider that would be adding power to the deadly blade, also too chicken to trust that head from coming off. i might use it as light balancing off some limb compounding the stability of my lifeline. i am picturing a 'wider' than tall tree for these examples, whereby high TIP is not available, and as you go out, the lifeline support angle approaches flat, like a certain 7' gi-ants head.
Another help i have found is a TIP from spread crothces so that instead of both legs of the lifeline being pairallel coming to me, they form a triangle as they come to me, for more side to side support/buffering. Sometimes, not having the TIP on the same axis as the walk can be achieved, then i can walk side ways with my weight leaning back perpendicular to travel, the lifeline acting as a stop, saying that i can't go over but so far, using the forces of the restriction of the line and the pull of gravity pitted against each other to keep me locked in place.
If the walk is fairly a clean limb, i run my lanyard under the limb as a 2nd safety; but also have it sized where if i tighten up my lil'knees, the lanyard is so tight that it is stabilizing me, then i walk with bent knees; only tightening them to stabilize at critical points. i have also sometimes used a choked sling as a sliding handle, and have tried to concieve of one with a wire inside that would self open the choke when not loaded to slide more easily in between stabilizing activity!
After the diameter of the limb gets less than 1" my feats hang over on either side as my shoes are now wider than the limb, so that the sidewalk effect is less effective, effectively for that effect that JP refers to. i showed it to him when we went two diffrent schools yogether, in diffrent states. For those extremes i willingly violate OSHA, Labor and SPCA precepts as i ride on the back of my pet ferret, which also saves energy for the work, though not for the ferret, hence the conflicts with danged govern-mental boyz.
First liar (t)ain't gotta chance 'round these partz! Ya shoulda lernt dat bye now!
-KC