Tapered hinges are the shit. There's no point in fighting the thicker compression side of the hinge trying to get it to bend over.
There's also a good reason to leave the tension side of the thicker.
In general, the way I see a tapered hinge is you have the "right" thickness hinge when looking at the tension side. Having a straight hinge would mean you had to force a lot of compression wood over, which has no advantage in most fellings. By tapering the hinge you're leaving the hinge thick where it needs it and cutting the troublesome wood away.
In and of themselves, the wedges in the back cut don't dictate the direction of the fell. Hammering them in to lift the compression side doesn't help. Hammering them in the tension side is putting extra strain on the hinge. Putting the wedge in the back gives you the most leverage to lift the tree, closer to the hinge gives you more lift for more effort.
If I need the extra lift, but the tree has a lean like the smaller one, I definitely hammer hard into the compression side before I'd go to the tension side. No point in trying to break the hinge.
The height of your back cut is fine. In our part of the country above a negative height (respective of the apex of the notch) is fine. The ledge allegedly prevents the trunk from kicking back over the stump when felling up hill or through an obstacle. Pine is a great hinger and thus the hinge will hold the tree to the stump preventing the trunk from jumping back and getting the cutter.
On the shot of the tapered hinge, your thick side could be half as thick and still be twice as thick as it need be to drop the tree with the limbs still on it, much less with the lean side weight removed (spars).
The compression side looks fine for dropping a full body tree, a touch thicker than I'd go. For a spar, it's about twice as thick as I'd go.
The more hinge, the harder it is to go over. That can be handy for trying to make something go over slower. Tapering the hinge and gutting it (removing the wood in middle 1/3 of the hinge, give or take) are both ways of removing insignificant wood to make the tree easier to go over. Making it easier to go over reduces the chance for barber chairing also, but in normal pine, that's nearly unheard of.