Update: Empirically, my home network is much better behaved with the tweak I noted earlier. I'm still having some issues with recordings, but it seems like Myth only wants to use one of the three tuners on the HDHR box, despite all three showing up in Myth-setup, but that's a separate issue.
Any delays seeing the Home Sharing server are due, at this point, to having to wake the server from sleep, it seems. I'm not getting random network outages.
Any delays seeing the Home Sharing server are due, at this point, to having to wake the server from sleep, it seems. I'm not getting random network outages.