I keep looking at the OP's pix and they look round.. But the view is so far away, that it is hard to tell. OP, it might help if you could post close ups of the head gasket, perhaps 1 of the front 2 cylinders and another of the back 2 cylinders.
Also, could you post a pix of the bottom side of that head that you removed?
Which points out that it could be quite a number of issues.
