John, I have to pop in at this point to say those ideas for the metronome sound great. I've got a bit of a thing for 7/8, so anything that makes it a bit easier to deal with if I start using loops would be welcome.
That said, in my head I don't really see 7/8 as any different to 7/16 or 7/4 or 7/2. There's a pulse, the pulse happens seven times within a bar, and that's it really.
I can't really see how loops can work out without them being made for 7-beat bars though.