Well I don't know much about those types of onions. I just plant my bulbing onions thick and use those as green onions as I thin them out. With chives I cut them back or let them flower and eat the flowers. Is it possible spring/bunching/scallions have edible flowers too?

I assume you planted them from seed? just keep thinning them out and they will keep growing until winter.

I get a couple of seedling bunches already growing from the nursery in early Spring, they grow vigorously in a "bunch" and keep growing until freezing. The bunch sends up more stalks. I prefer eating the raw scallions in Spring, as they get stronger tasting and tougher in Summer, which is the advantage IMO of planting early seedlings in early spring.

You can keep cutting off the green stalks and more will come up, similar to an actual Chive plant. Some do flower but not in group like Chives. I've had Scallions (Evergreen Bunching) survive an Ohio winter and grow again the next Spring but I don't like the quality as much as new seedlings, so I just dig them up. They make a big clump.

As a market gardener selling green onions or scallions, I plant every week. I grow from sets and plant 500-1000 sets per week. Early is the growing season I thin them out and leave some to bulb out. Now I just harvest the bigger ones and leave the smaller ones till next week. I plant sets 1" apart in 24"wide beds so 500 sets takes up very little room. 2-3 square feet can grow a lot of scallions