There's no need to separate DVD and CD playback. You are getting no data to the sub when listening to CD's because your mains are set to large. We could make a chart such as you are describing, but I think it would overly complicate matters. I put this overview of bass management in my 950 review, which may help you. Here's the overview of bass management when using digital inputs or analog inputs that aren't in bypass mode (it treats the crossover points as absolute cutoffs, which is inaccurate since they are actually slopes, but it explains the signal path at least):

• lies to all digital inputs and all stereo analog signals that do not use the "stereo bypass" mode
• Any speakers set to large will receive full-range signal with no data sent to the subwoofer (crossover setting is ignored)
• Any speakers set to small will receive all information above the specified crossover and nothing below the crossover; data below the crossover is sent to the subwoofer
• subwoofer will receive the LFE channel of multi-channel soundtracks as well as any re-directed bass from small speakers
• If there is not a subwoofer (sub turned off in the menu) and the mains are set to "LARGE," then information redirected from small speakers will be sent to the mains and the LFE channel of 5.1 soundtracks will also be sent to the mains

If you are looking to get the subwoofer involved when listening to CD's, you will need to set your main speakers to "small".