Unfortunately there is no reference I know of in existence that contains this kind of information.
What I can tell you is that P00XD302 is special in that it is specifically designed to work with the SRST / IP Keyswitch router features, and right now they are the only loads available to use with that feature.
Any other load that is currently available with CallManager 3.0 does not have the support for this, even though in some cases -- like P003D310 -- it may look like it.
When CallManager 3.1 is released, I have seen so far that all of the loads support the SRST / IP Keyswitch functionality, so I don't think you will need to use "special" loads any longer at that point. When this happens we will probably have some more specific information about that.