There's no need to replace the outermost socket. Just use an 8MB Simm in the third socket, this will give you the same memory as two 4MB Simms in third and fourth socket. Same wth first and second socket: Either two 4MB Simms there, or one 8MB Simm in the first socket, leaving the second empty.
Another clean way of de-soldering the socket (if you really want to do that) is a wave solder machine. Try to find a company that has one, spray a little flux on the bottom of the motherboard, and remove the socket over the wave solder. After that, empty the holes with a vacuum pump or solder wick (regulated iron needed, 4-layer boards can sink a lot of heat!), and put the new socket in.
Personally, I'd go for an 8MB Simm. If you can't get hold of one locally, try memoryworld.com - they have all kinds of legacy memory modules in stock, and they even have an Amiga specialist on the phone (at least an Amiga memory specialist).
Jens Schoenfeld
