Thanks! It is one solution and I think it may be the best idea. It requires the use of screws that would be cast into the fiberglass piece but as long as I get an accurate measurement of the two holes (center to center) I can make a jig for that. The only thing that gives me pause is today's speakers are heavier and I would prefer there be some way to connect the top part of the speaker panel to the top part of the dashboard. I suppose support pieces could be cantilevered back to the flat surface below the radio opening. That's a possibility.
