Hi Adam
As you will find with Takahashi you will need to look at the System Chart.
http://www.astronomy-electronics-centre.com.au/, look at the FS-60CB Photo/Visual System Chart.
I am not sure if you intend to do Prime Focus with a DSLR or not, irrespective, you will need either the Reducer or the Flattener to get a flat field with a DSLR, whilst not absolutely essential, the CAA is highly recommended for orientating your camera. As you will find, you will need to use the Tak Wide T-Mount as it is a metric thread.
I run the CAA, Flattener and Tak Wide T-Mount with my setup, although I haven't really had much of a chance to use the setup.
The clamshell can be attached to the Losmandy D Adapter, just use the center hole, it is threaded to take a 1/4 x 20 thread. That is what I use when my FS-60 is being used as a guidescope. The other two holes are 35mm apart and are used for attaching to an EM-11 or similar Tak mount.
Cheers