The drug stores will give you a graduated syringe for free, I try to get as many as they will give me. I ask at every drug store I go into. To get the Epoxy OR Gorilla glue into the slot or hole is easy with one. On slots I always drill a hole, about a 3/32 or so into the center of the slot and using the syringe I just squish it in the center hole. I can see when it flows out to the sides of the slot. Hinge pins I just squish it into the hole. If from trial fitting my controls the pin holes get sloppy then I use the Gorilla glue, it they are nice and tight I use epoxy. The expanding Gorilla glue is great on any of the over size holes.
Those are great videos by the way. I do have some small syringes diabetics use for adding just a drop of oil onto the hinge center pin.