The dose can be taken in the morning, given it much of the day to act. Acute effects seem plausible here given the neural connection to the gut, however, a self-experiment examining acute effects only is still useful to help rule that out. And to investigate slower effects, you can block the doses so instead you take a week (or a month) at a time (this is more work because you need more blocks to achieve similar numbers of units as a per-day randomization).

> my experience is that alcohol can affect the gut flora.

So? You don't know if the alcohol effect would be to enhance or reduce the supposed calming effect or not affect that at all.