Hi Caster
Really, really please don't use Basil at night and CERTAINLY NOT IN A BATH just in case you were thinking of doing so!
I agree with Valerian, however it is expensive and I would only ever use one drop per blend. Hop oil has a similar effect - again it's expensive and only one drop per blend.
More commonly available oils: Marjoram, Chamomile Roman and Petitgrain. Ratio: 30 mls carrier oil, 6 marjoram, 6 petitgrain, 3 CR.
Hope this helps