[tim]

Michael, the glovebox dash from EM comes with the opening already cut out and aluminum flat head bolts counter sunk into the dash and welded in protruding towards the back. I purchased a blank dash and had to do what you are describing. EM provided me with a drawing that also showed the location of the mounting holes, and supplied me with the aluminum screws to weld into the dash.
You are correct about the door mounting from the outside and being clamped between the dash and the glove box. I also ended up mounting my latch from the top outside of the glovebox through a slot instead of the top inside to get the striker to align properly.
Why are you painting your dash before covering it?? That sounds like extra work.
Tim