I finally have all the instruments after the vertical card compass, altimeter and radio arrived. So, I went back to work on the panel, drilled the three screw holes for the altimeter then measured the location of the pressure knob and scribed it onto the panel. Used a cutter in the dremel to carve out the half round opening.
Test fit the compass and it looks like it will just fit in its hole under the altimeter. However, the corner of the radio is hitting the corner of the altimeter keeping it from being turned square with the panel. I will have to figure out if I can safely file a little off the corner of the altimeter or if I will need to swap locations with the radio and compass.