I agree with Paul, the stager will end up in random places, and thus you will have butt joints in between openings. But once you start the stagger on one side, you can easily transfer the butt joints to the center section where applicable. You may have to scribe a line with an xacto knife and put graphite in it, on the joints added afterwards. But stain will also get in them to make it appear that you have individual boards in the center.Athwartships - had to look that up. Looking forward to using it in a sentence of my own one day.
Mark, I'm not buying what you're selling with regard to butt joints along the centerline. I would think the pattern you have selected will necessitate breaks between the deck openings... Just mentioning it before you get too far along. Or perhaps I misunderstand your plan - my wife assures me I have an affinity for that...
Also remember when adding planking not planned for by the kit manufacturer, there is a good chance the supplied amount will run short. That happened to me on the NL and I had to order more matching wood for the decks.