72 scapes, yay!
Your seedlings look marvelous, Sue.
My seedlings are planted in a grid in raised beds, each seedling in a 6" x 6" square. (The grid is for drip irrigation.) That 6" spacing in any direction is not too close, and most seedlings will bloom, provided there aren't any weaklings that get swamped/shadowed by bigger neighbors. Out of 3 beds, the only one we are having issues with is half of one bed (also two edges), where first a critter chewed the irrigation line, then when that got fixed, we had another leak elsewhere.
That said, I'd be nervous about the 4" apart planting, simply because your seedlings WILL propagate, and then you might have issues figuring out which fans go with which seedling. I had one seedling go from one fan last season, to five fans this season, and it's crowding the drip grid enclosing it. We'll be digging in September or October; hopefully it will stay contained in its 6" x 6" square until we do dig.