Personally I'd make sure I had separate disks for backups. You could put logs there or tempdb if you want, but if you lose data drives for some reason, make sure backups are elsewhere.

I might do either of these, depending on space.

- 2 disk R1 for OS

- 2-4 disk R1/R10 for backups (maybe logs/tempdb, depending on space)

- 10-12 disk R10 for data

or

2-6 disk R10 for OS/backups

14-10 disk R10 for data/logs/tempdb