In a perfect story world, the signposts happen simultaneously. HOWEVER, in the real world we dole them out in bits and pieces over time, and thus the need for Storyweaving. There are no RULES for storyweaving, only guidelines. For example, it's generally acceptable to finish weaving all four throughline signposts (e.g. Signpost 1) before moving to the next signpost. However, the Journeys, by definition, embody the transition of one signpost to the next. So, though it might be clearer 'logically' if all signposts are completed before you move on to the following journey or signpost, the reality is you can follow your gut and inter-cut and overlap them as you wish.