Green Mountain multiplier onions

Harvested the Green Mountain multiplier onions yesterday. I have questions!

background:
Started them February 2025 from seed purchased from Experimental Farm Network.
Planted in a raised bed July 2025.
Overwintered with hoops and frost blankets.  
We are zone 7b southern NJ coast US

So 22 seedlings made it through the weird winter. Some threw up scapes; most did not.
As you can see from the photo, I have around 40 bulbs. Some are red. Most are white.
I'm drying them now.

So here are my questions:
I'd like to hold back some bulbs to replant. I use the side shoots, right? The smaller bulbs?

Should I put them in at the end of July again to over winter?  

Thanks for the advice!