Training camp RNG poll: at what point does the RNG system decide which hero you will pull from a TC?

Based on my experience, the RNG determination of what hero you get happens when you click on the hero icon to collect it. I had a hero ready to pull from TC20 when I imported my account data to the beta server. In beta, I pulled Joon. In production, I pulled Renfeld.

My guess is that on a 10x or 30x, there is a full transfer of all the heroes you’ll get in one data burst, rather than 10 or 30 separate calls.