Guidelines are designed for row planting with rows to walk through. If you can access your bed from all sides, you don't need to provide a walkway in the middle. I plant between 18-24 inches apart in all directions. I want the leaves to be almost touching when they are fully grown. This maximizes the ground covered. Shaded ground = less weeds. I would use the spacing between plants for spacing between rows. Actually, I offset plantings. It is an intensive way to plant that maximizes spacing. Offset and under planting allows you to grow a few more plants in the same space. I can get 3 plants in a 4 ft length. I will plant the outer ones closer to the edge of the bed so it will actually hang over the sides of the garden.
Happy gardening in Hawaii. Gardens are where people grow.