Here they are, fresh out of the bag. Note the flat side and curved side.
First one is in, notice how nicely it blends with the frame ring. Simply bolt in with the allen wrench, curved side facing where the shoulder hubs will be.
And alas, all three are installed. Later on down the line, the real fun will be trying to figure out where to drill the holes in the skin so they line up with the block holes! But that is for another day.