How much faster does sublingual melatonin take effect compared to the pill form, and do you have any idea what dosages would be comparable?

Sublingual faster: Yes the sublingual melatonin is absorbed faster. I would estimate that it is absorbed 50% faster than the oral. As per the doses: with sublingual melatonin you absorb 50% or so. With the oral medication it is more like a third, but there is a wide range. Because there is a wide range for a given individual the absorption could be roughly equal for both delivery systems. Follow your MDs advice.