I'll see if I can find the posting. It was a fairly exhaustive article. It was enough for me to give it a try.
EDIT: I think this was it. Looks like it's had a couple of turns here: https://news.ycombinator.com/item?id=17632668
EDIT: I think this was it. Looks like it's had a couple of turns here: https://news.ycombinator.com/item?id=17632668
What I ended up doing is buy smallest dose of melatonin gummy-bears (3mg afair) and they were easier to cut into smaller pieces/lower doses than pills.
I occasionally use these to adjust my circadian rhythm. Naturally I go to bed around 2-4am but I have kids that wake us up at the crack of dawn.
Edit: looking around a bit, it does seem like melatonin or supplement ingredients are added and mixed before they are molded, so at least in theory it should be spread around fairly evenly.