Angle Shades Pupation

[xSarahx]

I found a fully grown angle shades larva on nettle, on saturday. I kept it in a caterpillar breeding cage with some potted nettle and it seemed happy enough. This morning i found him at the top of the cage, so i presumed he was ready to pupate. I filled flowerpot filled with dry peat and misted the surface a couple of times with water, then placed him on top. Over the last couple of hours he has made a nice little cocoon by moving pieces of peat around him and sticking them in place with silk threads.
I was just wondering how damp/dry the peat needs to be, and does it need to be misted occasionally?
Thanks

(ps. how long do caterpillars stop eating for before they shed their skin?)