It would appear that he didn’t really understand about map projections, either. Smaller scale regional maps shown on the news show the eyes not level with each other - the Nebraska ring being significantly “below” the Iowa ring. They are about a degree different in actual latitude.
However, on the right projection of the US, such as you might find in the Rand McNally road atlas I’m looking at, the eyes line up fairly well on the page, and are fairly well centered. If you want to guess what he was going for, you probably want to look for a pattern superimposed on such a map without regard to the underlying actual coordinates. Say, a polyconic of the contigous 48 states arranged so that the tip of Maine and Seattle are at about the same height on the page at each end.
That said, Salida looks way too far west for the edge of the “smile” part of the smiley. Amarillo would fit very well. Perhaps Salida was part of the outer circle. Perhaps he wanted to throw in a few “red herring” bombs to keep his pattern from being too obvious until he was closer to being done. Perhaps he simply changed his mind. He’s a nutjob - who knows.
It also might seem that he could have drawn neater circles in Nebraska and Iowa. I’m guessing that they may look a little more ragged on the news maps than they are because he placed bombs in rural mailboxes, and the news agencies are marking nearby towns rather than the actual locations.