Coco is another learning curve. I would stay with what you have. To pop beans I just persoak my 1 inch cubes of rockwool. Then take the rockwool cube and sling the water out like cleaning a paint brush, to get excees water out. Place a bean in the top and cover slightly and keep in a warm place. 3 to 5 days and they pop. During this time I only put a few drops of water on them if the cubes look like they are drying out.

I just made the mistake of putting a bean in with clones, which are in 1 inch cubes but I keep about a 1/4 inch of water in the bottom of the tray to keep the stems wet. Well the bean popped but i left it in there and it died from damping off. Too wet and the root will rot and fall over. Too bad it was a redbud skunk fem.

Seedlings need no nutes untill 2 weeks old. The less you can move a bean around the less chance of damage to the root.

I have seen your setup with the gallon bags and if you are only using 1 inch rockwool I would not think they would be under water when you flood.
I need to look at your setup again.

Listen to tiny about flood times.