FIM 2010 r2 password reset design using two servers

I plan to use two servers for FIM r2 SSPR. The database server will be hosted in a third server.
How should I design these two server with respect to what services gets installed? Since this is to be used for only SSPR, are there services that don't need to be installed? I plan to use sharepoint foundation. The test lab site and other technet articles weren't much of help as to what specific services need to be installed.