Hi Willem, Welcome to the site. I am sure you will find info here. I owned a '58 beetle many years ago. I liked it a lot but some idiot wrecked it by jumping all over it then smashing the screens when I left it outside my workshop because it broke down and I was waiting for parts. I have a friend who restores and customizes beetles, his name is Simon Emery, he is quite well known here in the UK. Here is a link to his website I think you may find it interesting.
http://www.thepaintbox.co.uk/ Simon and I have been friends since our teens. I taught him and his business partner metalshaping techniques many years ago.
David