I screwed mine up. I tried to put the jacks in the middle of the face, but I was getting frustrated when things turned into a Lord of the Rings movie. Every bit I used to drill was walking north on me. Then I figured out that there is a cross support running down the middle of the face inside. I ended up with four useless holes. I covered them with tape and started over.
By golly, when I double checked myself and did it right, it came out okay. I measured out where the jacks would go, and drew them in with pencil. Make the boxes and then put an X in the middle. Start with a really small drill and drill a hole on your X. Then get a bigger bit and repeat on and on until you get up to a 3/4 in. A 7/8 in. drill bit would have been perfect, if I had one. Instead, I routed out the hole for the wings and the push release tabs with a dremel. When they went in, I drew the spots for the holes and drillrd them out for screws. I just used sheet metal screws to hold them in. Then I wired it up and voilá.