Unfortunatly you got one of the harder grains to crush. I used a wine bottle with a paperbag on a cutting board.I hated the plastic bag it ruptures and probably embedds pieces of plastic in the grain.Its ok for small amouts ,but i just crushed a few oz at a time. Be prepared 3# may take you about an hour+ to crush.Good workout though,maybe some sweat too.
After going from partial mashes to more or less all-grain, i got a$55 corona mill.Fresh,crushed grain in no time and i swear my batches are better and my efficency as a bonus,not that im that hard up for efficency. You can still get good crushes from rolling it.
And yes you want to lay out one layer at a time dump repeat.