Kick panel speakers

I was looking to put some kick panel speakers in an extra set of panels I have and was wondering what speakers some people have used and how you mounted them. I took the driver side panel off and the sheet metal behind the panel is flush with no useful indentations. I measured the spacer leg that the mounting screw goes through and it's 1" long so it looks like I only have a depth of 1" for the magnet. Of all the speakers I've looked at the shallowest was 1 5/8" deep. I'd love to hear some solutions- thanks.