When to top an auto?

Hey! I would never say that 😅. Autoflowering varieties have too short a growth period to properly recover from a topping that will slow down their growth and therefore likely decrease the final yield. If you want to get the best out of it, you should try low stress training instead, which will allow you to expose as many new shoots to light as possible and get more main colas. I hope that helps and good luck!