Help with Rockwool mini cubes

I'm trying to get a grasp on how to use Rockwool mini cubes. I have a tray of smart pots filled with mini cubes in flower atm and I'm hand watering them.

Now I know hand watering Rockwool is probably the worst way to use them ,but it's all I can do right now.

So here's a question. How often should I hand water them? I know I shouldn't let them dry out completely, but should I water even when the pots are heavy? Perhaps water daily regardless of how heavy the pot is? I have deficiencies galore in the tray I am handwatering, run off is pretty high at 2.5ec and pH is 5.8. Hella high ec so I plan to water with a very mild nute mix tomorrow, but pH is surprisingly on point.

Also, I just put some plants vegged in smart pots with mini cubes. I just put them into flower directly into my ebb N grow bucket system. These plants have been handwatered through veg and are surprisingly healthy, and I'd like to keep it that way, so here I am looking for as much info as I can get. Today was the first day I set the buckets to flood for 15 minutes 1x a day. They are 4 days into flower.

I plan to flood the buckets so I have 3 questions.

What should the water level be up the buckets when flooding? The buckets are 8" tall. Should I flood 1/3 or 1/2 or 3/4 up the pot ?

By not fully flooding the pot, this seems that would kill some roots at the top that are not getting wet, correct? If so, I would not be able to top feed at all after this happens because it would create rot from the dry dead roots, correct?

How many times do you flood Rockwool mini cubes?

Thanks in advance, I hope there are some die hard Rockwool fans that can help me here.

Here's the gear, the tray looks shitty, probably not much I can do here except try to avoid them getting any worse. Someone please walk me through keeping the buckets happy and healthy

The rockwool mini-cubes are the same material used to make the bigger blocks (i.e. same mix of absorbent/repellent fibers). This particular mix is excellent for plant growth, but it doesn't wick water upwards very well. Therefore, I like to get at least a 3/4 flood depth on the blocks and the same would apply for mini-cubes. Since you are in a fixed container, I'd probably try to flood those almost right to the top.

The quantity of flood cycles/hand watering is a judgment call. If the pots are getting light by the end of the 'lights on' cycle, then another flood cycle would be advisable. The max EC I run is 1.2 - but I want the plants healthy to the end. Some people enjoy plants that are banana yellow from top to bottom at the end. That's not for me.

Also note that rockwool can accumulate phosphorous over time. That's a feature, not a bug...for flowering plants.