My in-dash speaker solution
All the brackets I made are for 3.5" speakers, except for one that was cut for 4" speakers. Go up this thread a bit and see the three links I provided.
My son Aaron put the Volfenhag speakers in the front of his Dart Sport and 6"x9" in the package tray. He will use the Volfenhag again in his '74 Duster, but it has the fold-down rear seat, so we need to come up with something else for the rear.