While im interested in all this stuff im not qualified to comment much on it, im a firewood guy who just has to get a tree on the ground without hurting myself.
I cut smallish wood on mostly flat ground for fire wood. I do conventual notches to keep the stumps low so I dont have to recut them after I fall the tree. The stumps need to be low to get the tractor and log loader over them. The wood is either skidded out or cut 8 foot for a log loader, any short block that gets cut off the stump because it's too high gets left in the woods.
If a tree is leaning the wrong way, I let it go that way and drag it out of the mess it fell onto with the tractor.