So any previously loaded music on the 'new' slave would not be seen by the player at all?

Hmm- I could pop the "2nd" drive into the unit as a single/primary, then use emplode to delete everything, then reinstall the original drive as primary (and the jumper on the 2nd)...

I guess I should get over my fears of HyperTerm and Bash prompts. This kind of a project is good for familiarizing myself with it all.
When you say 'wipe', how are you thinking I should do that?