Yes, thanks andrewt & therother.

I'll have to develop the patience to do one turn several times over varying little things here and there. It was nice to see (just now, after reading the responses here) that if I reloaded a turn and did the exact same sequence of actions, I got the exact same results. I was worried that even that would vary widely, apparently not.

I did get a memory editor today. How to use it for research, that's a different matter entirely!