Today I demolded the mycelium slices and stacked them. The cups do seem to have taken up more space in the mold than the last spacers I used, which explains the extra mycelium I had. Since my oven can only fit 3 slices stacked at once, I chose not to add the fourth slice at this stage. I might add it after they are fully dry, or maybe not at all.
While stacking the slices, I tried to press them together a little bit to help fill in some of the gaps that were left in my first attempt, so we will have to see how that works.
In a few days I will try to pull the plastic away so the mycelium can grow the white coating over it, then I will leave everything out to dry.