The scientific way to tackle caffeine would be to understand when the benefits are replaced by the deleterious effects. So many plant derived compounds exhibit such so called hormetic effects, by which very small amounts are beneficial, higher amounts are deleterious or even toxic.
What are the concentrations above which rajas, or even some sattva, turns into tamas? It is told 300 mg per day, even though it may change substantially depending on individual metabolism.
You may also question to what extent any plant is deleterious when taken in small amounts. Since people like John Sinclair were thrown into prison 20 years for having two joints (marijuana) at one time here in the states.
