Here is a 16-stem configuration for reference:
1. Stem 1 - Kick
2. Stem 2 - Hat 1
3. Stem 3 - Snare
4. Stem 4 - Clap
5. Stem 5 - Ride, Cymbal
6. Stem 6 - Rest of Kit / Percussion
7. Stem 7 - Bass
8. Stem 8 - Piano
9. Stem 9 - Synths 1
10. Stem 10 - Synths 2
11. Stem 11 - Vocals
12. Stem 12 - Background Vocals / Vocal Efx
13. Stem 13 - Strings
14. Stem 14 - Atmospheres, Swells
15. Stem 15 - Return Efx 1 - Reverb, Delay, Etc
16. Stem 16 - Return Efx 2 - Flanger, Long Delay, Etc
Please remember to render your files at 24bit and at least 44khz. Between -3db -6db is of head room on each stem is perfect for me to work my magic.