1; If it's good for you, it's good for the shrooms.
2; light from the room is good enough, if you can see the cakes, it's light enough.
3; If the seal on the terrarium is tight, Perlite should be good.
4; If water drips on your cakes, you need a drip shield, if it dosen't, you don't. (my friend never usues one)

As I said, ALL of these answers can be disputed by different factors, but you'll find that out as you advance and learn. Keep reading around the site and good luck.

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Away!