Dividing/Not Dividing Onion Sprouts and PRR

I was curious if anyone else grew this way:

Last autumn I had some stored onions begin to send out new growth. I thought it would be fun to plant the whole Onion and watch it. As the bulbs began to divide I lifted some, divided the bulbs, and replanted them. Others I left alone. When harvest time arrived I noted that both groups of onions were very uniform in size compared to years past when I would start from seed.

Does anyone have any tip/tricks they've discovered growing this way?
Has anyone dealt with PRR issues growing this way?

I do this every year with whatever onions start sprouting in the kitchen. Never bothered dividing them though, just shove the whole thing in and let it do its thing. Interesting that your divided and undivided came out similar sizes. Makes me think the energy from the original bulb matters less than the growing conditions once they get going.

Thanks for the reply Joao, about how many onion bulbs does the original onion divide into at your garden? Do you use any fertilizations?

When I lifted that bunch of onions in the above picture I quickly realized their dome-shaped growing pattern made a really nice home for slugs...