So I did a trial run to see which way to go. I figured the center one would be the hardest with console, radio and AC diffuser in the way. So I tried to install it with glovebox liner out and defrost vents removed. Pain in the ***, gave up after 20 minutes. Tried over on far drivers side, again a pita. Said screw it and they are going in from the top. Fingers crossed.
Mike if you attach with bolt from bottom the u nut or has to attach to metal dash frame as @clementine posted. The dash when squeezed to cowl of car lays flat in "cutouts", no room at all between car and dash frame. You could tack nuts to very outside of frame, but that's not happening, I just had it powdercoated. Screws are a #10 to match the u nuts.