Right on Ginny! It is worth a try, very likely to work. Looks like we may rely on you to renew seeds for next year
You can also replant harvested green onions, keep the outer layers intact, chop off the top leaves (to prevent moisture loss) and roots (leave 1 inch or so), then lay them sideways and bury the stems in soil. New big shoots would come up in spring.
You can also dry your green onions for storage, like you would with other onions and garlic. After harvesting, lay them out on the ground under the sun, then bundle up the dried stocks and store. You may be able to leave them outside for the winter. They may freeze solid, but will thaw well.
****Ginny, I will send you some other onion seeds for you to try later, since you are such a pro at growing things. I have just harvested seeds for Mammoth Improved Onions, which I bought directly from Robinsons in UK. "After years of research this onion has now reached a high standard of vigour and uniformity. Can be grown to over 6lb in weight and 22" in circumference. Very sweet flavour. The exhibitor’s onion winning many prizes from the 1800's to the present day". Mind you, mine only managed to survive and produce seeds, they are not a lot bigger than regular ones in my garden, they suffered neglect and drought, and I certainly did not start seeds indoors in November to get to the competition size. I may offer some of this at our next seed exchange.