tom tom staff

[胡海鹏 - Hu Haipeng]

Hello,
  I'm about to add a tomtom part to my overture. It only needs 3 toms, so I think only 3 lines are required. Then here's a visual problem:
  When I set the line-count to 3, will the clef position 0 be the middle line? If set line-count to 2, which is 0 and which is 2? Or will the other line be -2? I must know this to ensure correct placement of percussion clef and notes.

regards
Haipeng