Step 3 - It's Alive!
Slime mold woke up and moved out of its paper and onto the oat. It's nomming and growing now.
The two original sclerotia didn't activate, so I used 4 samples more with slightly different conditions. 2 of them are doing great, the others not so much.
I didn't properly measure or jot any data down, so this isn't Science, but now I have a general idea of how this works and I can go for precision next time.
8 year olds are better at this than me.