Since reverse headstocks put the tuning machines on the other side of the headstock from normal headstocks, you will want the opposite orientation.
For example, if you are a right handed player, on a standard 6 Inline Headstock, you would pick Bass side tuning machines or tuner upgrade kit. Since your headstock is reverse, you will need to pick a Treble side.
If you are left hand dominant, the scenario is reversed. You would normally pick a Treble side kit or Tuning machine but since your headstock is reversed, you will need a Bass side.
Related Article: What's the difference between bass side and treble side?