Does anyone have definitive and complete info on how to get snd_bt87x working correctly as the MythTV audio source for a BrookTree-based tuner card?

I have been trawling these forums and Google for 2 days and been getting nowhere. There are lots of partial accounts of problems but it seems as if most people give up and use a cable instead.

There seem to be too many variables, especially for non-Linux experts - there are simply too many possible combinations of settings to work it out by trial and error.
I don't think I am the only one looking for this info, so I think it would be useful to record here.

The specific questions include:

- Which cards does snd_bt87x support?
- How is the audio represented in terms of a device /dev/XXX?
- What additional modprobe.conf settings are required?
- (Assuming using ALSA), what additions/changes to asound.rc need to be made, if any?
- What audio device should be specified in the Capture Card settings in mythtvsetup?
- What audio sample rate should be specified in the Capture Card in mythtvsetup?
- How does the device /dev/tvaudio that seems to appear automagically relate to snd_bt87x, if at all?
- How can one test whether it's working in a simple, isolated way, not dependent on MythTV?

Thanks in advance to anyone who takes the time on this.