A Spacing Issue

So the instructions for the summer squash seeds I purchased said "Sow 3 seeds every 12" (thin to 1 plant), 1/2-1" deep, in rows 5-6' apart." Sounds good. Because I have quite a bit of space, I gave them a generous two or more feet between each plant in the row. Well... you can see below, not all squashes are created equal.

Here we have two enormous plants flanking a much smaller one. The big ones are my patty pans (Sunburst) while the one in the middle is a straight-neck yellow squash (Slick Pik). The poor straight-neck is barely hanging on in the shade from those big bullies! Clearly it was unwise to alternate varieties along the row, but still... imagine the tangle of squash I would have if I had multiple patty pans spaced only a foot apart! Next year I'm definitely growing patty pans again, but they'll be given plenty of room to do their thing without crowding the rest of the residents.