Add an option to select critical post location points and have all posts between those points be evenly spaced based on a maximum distance between posts. It could work like this: select beam to attach to, select start and end, select nosing point (if desired), select critical post locations along beam. Posts would be placed at the start/end points and critical points - posts would be added by the macro between these evenly spaced based on the max post distance.
This would be helpful when placing posts to avoid obstacles (like concrete construction joints, electrical lines, heat coils, etc.) and also when placing posts on a concrete stair (to make sure posts fall on treads).