Ok so me and my friends started on a frankenstrat project which is now nearing completion. However I have hit a bump in my road by not knowing how to mount a pickup directly to the body of the guitar. Basically I know I need some kind of material underneath the pickup to make up for the lack of springs but is that all? Like could it be any kind of foam or sort? Thanks for the input in advance.
foam works, I had my EMG's on foam for a while until I had screws,

I've also seen bits of rubber under the pickup on the screw.

Wood? LOL no... that would mean you can't adjust it.
You can buy pickup foam from most guitar parts websites.