The think the other trick is having two people to double team the fish and each person armed with two nets, seems to make netting easier. I do like using dividers too
I found this.....it's 16". That seems like the right size for 12 inch fish? fine mesh to keep from messing up fish. Made for Koi in a pond.....
Look right to you guys?
https://www.thepondoutlet.com/home/tpo/page_3418