Cool, all of the above sounds good to me.
Thanks for greens, salad greens, cover crop and forage crop!
I'll think about "thin to distance" and "spacing", but I don't have any good ideas.
Whatever way the field or fields were set up, soil fertility, warmth, sun angle and day length could probably change the "optimum" by a goodly amount. Some harvest small plants early, others want to take a few big really mature plants.
With leafy crops, it makes sense to leave the seedlings 3 times too dense, and only thin them as you harvest the first 2/3 or the crop as they start to shade each other.
How could this be compressed into something palatable? I don't know:
Rows 12-18" apart. Space 5-6" apart within the row.
SFG: 2-3 per square foot
Intensive Raised Beds: 6-8" apart
Broadcast: N seeds per square yard or per 100 sq ft
Wide Band: band is W inches wide and sow N seeds per linear foot.
Maybe what we already have is best (even though I don't have that stat for most crops):
"Plant Width" tells a gardener whether to start out with it "dense" or "thin", and then they learn from their first crop what would work better for them.
Johnny's and other farm-oriented seed vendors have tables of # of seeds per 100' of row, or pounds per 1,000 sq ft or per acre. On my scale, that doesn't help much.
I usually look for the "spacing within a row" and then use around 1/2 that separation in both directions. Then I expect to thin 1/2 or more of the seedlings before they touch, if I have good germination. I intercrop something else if I have poor germination.