The corn grains are not edible when fully mature unless ground up as you mentioned. Think of eating popcorn before it's popped. The time from sweetcorn eating stage until fully mature is a month or more.

With 4 plants the planting pattern won't matter much. Just plant them right next to each other, say 18-30 inch square, and hand pollinate. Collect pollen in early morning and apply it to the silks.

Too bad you have such a small space. Corn can be fun to grow! Like Fruitnut says, for that small number of plants, hand pollination is the only way.

Keep in mind Black Aztec is a very tall variety, so you might need a step ladder to reach the tassels to get pollen.

I know some catalogs carrying Black Aztec say it's a 'sweet' corn, but I take that with a grain of salt. It's a 'dent' corn that happens to be a bit sweeter than other dent varieties in the milk stage, and as far as I know it lacks the so called "SU" sugary gene mutation which is the foundation of modern sweet corns. If you are looking for melt-in-your mouth sweetness from this variety, you'll be very disappointed. Roast the milk-stage ears for robust corn flavor, or let it fully mature and dry for grinding into meal.

If instead you want a sweet corn that still has some color to it, you can try Ruby Queen SE or Indian Summer Sh2.