I may be missing something, but I seem to recall that you said these trees are in a location where they are not endangering anything, regardless of where they fall.
IF this IS the case, not sure why you need to use a rope/cable/chain at all...BUT tying off to a secure point can give you some security that if you evacuate the location the tree will not fall in the direction opposite the tie point. PROBABLY...
The probably is accurate and usually comes into play when the hinge is cut off partially or entirely. Cut the hinge off and it gets really random very fast. Cut off one side only and about 3/4 of the time it will rotate toward the severed side and fall 90 degrees from the face cut regardless of how many ropes are in it. Seen way too many that went wrong because someone kept cutting until it fell and it didn’t fall until totally cut off.
That’s the reason I tend to over rig these days now that the safety/efficiency balance we had with the tree service days has swung way over to the safety side. Felling can be routine until the tree leans backward on the back cut and traps the saw or you’ve cut all you can and the darn thing just won’t fall. A reasonable rope/cable and adequate tractor/truck setup helps a lot with that. I’ve gotten to the point I ideally prefer to have the 15K bull rope tied to the base of a substantial tree, pulled snug, and have the 9K rope tied to the middle of the 15K pulling perpendicular. A little tug on the 9K with the tractor provides a lot easier persuasion than a felling wedge and sledge hammer and I like the distance better than standing right by the stump. If it gets hung up in another tree, having a rope already in it also provides a swell handle to snatch it out.
Heavy leaners, dead, hollow, or lightning struck trees of some size are good candidates to have a couple of rounds of 3/8” grade 70 chains wrapped around with load binders snugging them up.
Don’t do all that or any of that all the time but I do tend to spend more time and effort over rigging than trusting my ability to jump out of the way of a tree that does a barber chair or goes the wrong way. These days I’m not in a hurry felling trees.