Which version of Native Client should be installed ?

Hi,

We have to install SQL Server Native Client on a Windows 7 (64Bit) workstation.  The database connected to is running SQL Server 2005 (32 Bit).

We would like to know

1) Should we install 32 Bit or 64 Bit Native Client on that workstation ?

2) Can we install SQL Server 2008R2 Native Client - Does it backward compatible with SQL Server 2005 or have to install SQL Server 2005 Native Client ?  This is because we are going to upgrade the SQL Server backend to Release 2008R2 or later version.

Cheers