So, I had trouble following the settings for recording two sides of a telephony call (skype), so once I found settings that worked, I figured I'd post them here for anyone else who might need them.
(Using a Logitec 250 USB headset)
System prefs : Sound : output and input set to Logitec USB
Audio Hijack settings : Source type: Skype (it'll restart skype if you have it open)
Skype prefs : output and input set to Logitec USB
None of this covers the audio specs - I'll be doing editing in Audacity to get those set correctly.