I opened a decent amount, and here is what I found during that time. In case you don't know a case equals 6 boxes.
Prime - 6 per box, 1 of each of the 6.
Legend - 3 per box. 3 of the 4 pieces.
Alph Lithograph - 1 in 3 boxes.
The one thing I found interesting is that the Alph Lithograph is NOT the rarest card. Normal Holo (Not RH) Red Gyarados is. RH Red Gyarados is not quite that rare coming in about 1 in 3 boxes, but the normal holo IS. It is about 1 per CASE, which was significantly LOWER than any of the other holos in which you would normally pull 4-5 per case.
Hope that helps,
Drew