guess he wants his car to do a few different things.
how i will be doing it on my 33 is to run a reinforcement plate attached to the frame work of the boot itself. then using spacers to the boot skin to run the bolts through.
This simply spreads the load through the frame of the boot instead of the skin itself - wont be a light weight thing but 6mm alluminium should be sufficient if the plate is large enough.