Took a few days and sessions, but I have the rear deck panel done.

Lots of measuring, trip to hardware store, grinding down 6x9 grills to fit over the 5x7 speakers!!!  I tried to mount the speakers directly to the sheet metal, but alas that turned to be near impossible.  Would have had to drill 4 holes through sheet metal with curves in it.  You know how difficult it is sometimes for a drill not to wander.  Try drilling in cramped space on sheet metal at 45 degrees!!  So I mounted them to rear deck panel.

Here are some shots of the trimming I had to do to the grills in order for them to fit over the speakers.

This is one handy bit for grinding away material.  Goes through plastic of course like butter.

All done, I think ready to put into the car.  Not in yet, though.