What would be the best way to mount 5 1/4 in the emty spot????

I glued a piece of plywood to the inside of the door panel and monuted my 5.25 inch speakers there. The panel looks stock on the outside. I also mounted a tweeter next to it. I'll take a pic the next time I have the dor panel off.

well i finally got my whole stereo installed,, well most of it, 2 5 1/4 in each door and two tweets in each door and a 15: sub in back got one more component set to put in...