What resin should I use?

[svn2002s]

Before i recover the rear shelf with new carpet (made it flat with a piece of plywood on the center), I would like to 'patch' the area where the wood meets the old shelf. I don't want to see an indentation through the new carpet. Any ideas? Saw some stuff on TV (street customs show) that wasn't fiberglass but can't remember the name.

[bmwman91]

Silicone RTV would probably work well.

[rooster]

maybe like Kitty hair or a 50/50 mix of bondo & fiberglass resin