Makes sense Ted, ill need to look into that more but could be exactly why we see these only on SC. You are thinking the sheets were printed with f & bs and then sorted by the big red sheet # to get cut and sent to the appropriate factory. Cool.
I've seen a Gilbert with a 30 and we know he is part of the 649 OP backs Tim describes and could be the centre bottom card for those sheets. As well, on the article sheet example the Sheckard & Goode are side by side because of this sweet card that Brian posted.
I really need to start a side by side grouping based on miscuts and front ghosts...
Keep it up guys, this discussion is great and its possible we could get a good start on a few sheet layouts.