Hi Andy,
That sounds like a reasonable approach. Although I still don’t understand how a hurdle_gamma / hurdle_lognormal family would capture bimodality?
Anyway, I’ve tried changing the family specification and now Stan seems to throw a problem.
I’ve opened another topic for this new issue here: https://discourse.mc-stan.org/t/brms-model-doesnt-run-after-custom-family-hurdle-gamma-specified/18365