I would also be interested in the "3/5 configuration", as I have a friend that uses 8TC, and he always wants to try something different. I assume it means to separate the 8 conductors of each positive and negative leg into 3 and 5 rather than 4 and 4, and then use 5 for the bass and 3 for the treble.
BTW, Bifwynne, did you have any thoughts on my suggestion on how to eliminate bi-wire in your setup?