Hi TIA,
I normally view 1,2,3 attendant options as bad programming. Kinda Notelish. You are right though. Do not use anything in your dial plan. This normally means avoiding 1,2,3 maybe 4 and 5. You can use 5,6,7,8,9.
The new R7 proc. is a 5X9 card - cool. I'm hoping to see 5 X 9 expansion cards. This will extend the density of a Partner system. If you need more extensions and not lines, there is an 012 card. That's 12 extensions, no lines.
From the sounds of it, you are using the PVM card (plugs into the processor). At some point (soon), the lack of voicemail ports (now 2) will have you buying the Partner Mail R7. You will never know how you were able to survive on the PVM card.
-Chris