I don't stack blades, I use one blade for the cut but I have an old Exacto BIG handle I use it with a single Exacto SAW blade for thin hinges and then I put in two SAW blades in it for the thicker hinges. Once I got a slot machine I only cut slots by hand when the machine can't fit into a tight spot. The slot machine comes with one set of blades but you can also buy a set of thicker blades for giant size flat hinges. Sometines I use some very hard balsa for a TE or LE, add some CA into that mix and the machine may not cut through it very well so I resort to the exacto knife again.
When I can I prefer hinge pins, it is so much easier to just drill holes for the hinges. Keep in mind, I'm a builder and don't have any ARFs so I can more often then not use what I like. ARFs have limits due to design and materials used. I cut my slots before I bevel the edges too, it's easier to align them and cut the slots.
I really am lazy and slot cutting wqas always something I hated, the machine is so much easier but still not as easy as a drill!!