Tractors pulling up at an angle loose pull- because the back end lifts, as far as nylon goes it cold flows at the knot under load and breaks
lets rethink this
two things to try, but practice on smaller trees first
A chain hoist has lots of pull and fine in and out control but most-NOT ALL, are pretty short, so get ALL the slack out. I have a 3 ton 20 footer ,also they sometimes stick and need to be played with .
second look into jacking the tree as additional lift.
Consult-D DOUGLAS DENTS '' professional timber falling'' A BOOK
I've felled problem trees using a 20 ton post jack and two --1/4 inch steel plates
not as good as a proper tree jack, as the jack starts to tilt at maximum lift
as for an anchor, Dig a deep hole , and bury a log with a chain on it -fill in the hole,
the side of the hole nearest the tree should be straight up and down with only a narrow slot for the chain
this is an army trick ,but they bury a truck tire and rim