i cut into the compression side first, so that the tensioned side holds the cut open; then coming from the tensioned side (fibre stretching apart, wanting to close on the compression side as tensioned/backcut side is released) sometimes out of line, but close enough for the fibre to fracture across to the other cut from the opposite side, leaving a 'Z' break line across the spar. This tends to disperse some of the force through the connecting crack between the 2 cuts.
Sometimes, i place a notch in the compression side, then cut through the tensioned (pulling apart) wood to the apex of my notch on the opposing compression side, to release tension as the cut walks it to a point of failure or folding, like dropping a tree. The stronger the hinge needed, the wider the hinge; the more relief movement needed to relieve the tension, the wider the facing notch cut. For the openness of the hinge mechanically chooses when the the hinge must sieze or shear. If the compressed wood is on top, placing a log under neath the soon to be 2 pieces, allows a smaller face opening; in that the log now doesn't have to sit down as far to releive tension. i think that bucking can be a good time for practicing and observing how hinging flows.
i think that there are times to plunge cut, some times just to help stay outta the dirt, others to cut away from the working hinge (safer); rather than towards. But it can be dangerous and hard on the nose bearings. Good way to line up cuts though!
We use plastic hinges, longer ones can build more helping force usually, though we use mostly the smaller, cheaper ones.
i usually work on the arms standing up first, but who's movement won't rock the tree, in this way removing as much force as possible, without disturbing the supporting legs; also getting rid of the higher risk overhead stuff first. i also notch these with all my skills and put them down slowly in a safe direction amongst the rubble. Then i come back through looking for any more easy, non stabilizing weight to ditch and things that could slap me if something rolled. Then cut notches in the compressed side of supporting legs and walk a backcut till they start to goto folding, as i step back; walking tension out slowly from the legs one at a time, using the buffered motion from a slow folding hinge to safely time delay fuse slow folding dissipation of force with me out of the way. Sometimes, tieing a notched and back cut supporting leg to the truck to pull it, causing the leg to fail with me out of the way when the log falls, rolls etc. If the face cut is towards the truck you pull the leg from the opposite end to close the notch. If the notch faces away, i tie right under the notch, so that the face can close.