I am amazed by the thoughtfulness of the Arviz/PYMC devs. I struggle with priors sometimes, although I have gotten better over time. It is still a work-on for me. Usually I muck around with the pymc random number generator, and az.plot_posterior. I know, not not great. I was trolling around Github and found that the Arviz folks had a library called Preliz (A tool-box for prior elicitation — PreliZ 0.3.1 documentation) for prior elicitation. It is very helpful! Well done folks.