Outlookers get a little complicated depending on whether they are structural or not. Typically around here we see them at 24" on center and they are usually structural. The top chord of the truss is dropped either 1.5" or 3.5" depending on if they are oriented horizontally or vertically. With structural lookouts the first lookout from the eave is usually non-structural since the dropped top chord truss will have a special slider attached to top chord to achieve the overhang. See image below:
Usually the sheeting goes on starting at the bottom so based on that the lookouts would be measured from the bottom edge of the sheeting so that they line up with the seams every 48".
I've seen a single vertical placed the ridge when the outlookers are vertical however what is common practice when the outlookers are horizontal?
Notice the different configuration of the top chord when the drop is only 1.5" (oriented flat).
If the overhang is zero then this slider or splice goes away.