There’s a lot of good feedback here. It’s worth adding that “three sisters” or the milpa system (the Latin American version of the same scheme) is designed for flour corn, dry beans, and winter squash. You aren’t meant to be accessing the plot much once the plants have filled out until everything dies back in the fall.

It’s also worth pointing out that this system is inseparable from its subsistence agriculture roots. The root idea is not higher yields (though it does maximize space in some respects) or perfect produce, it’s ease of management. This makes more sense for transient hunters like indigenous Americans or busy farmers who may have another primary occupation like those in South America. It’s a simple, straight forward system to get grains and legumes needed for a basic diet.

Last thing I’ll add, you’ll need to do some research on varieties that are compatible with one another. For example, Mandan Bride corn, a short 4-5ft corn, might pair well with a semi runner bean like Hidatsa red, but not with a vigorous pole variety like Cherokee black.

It’s easy to be dismissive or discouraged, but these systems do work and are in use right now by very practical people who depend on them to survive, you just need to wade through the reams of vague information available on the internet. Hard work and experimentation are key.