Psiloc(yb)in content varies a lot among fruiting bodies of the same batch, genome, flush, hell even within the same cluster (example papers [1][2]). So even for known/good sources I would suggest mixing at least a couple of fruiting bodies to have something known and repeatable. Since powder degenerates faster, honey is a good water/air/light free preservative.

[1]: https://pubmed.ncbi.nlm.nih.gov/17401967/ [2]: https://www.sciencedirect.com/science/article/abs/pii/037887...