You should do enough to fully water entire volume of the pot as best you can.
I have little sprinkler drippers with 8 jets of water. the top most area furthest away from 2 central sprinklers stays relatively dry, but within 1" deep it's nice and wet... something like that is okay. Water will absorb sideways and upward agains gravity to some extent, but that has limits. So, expect it to spread out quite a bit from the drippers and deeper it spreads out even more than what you see at top. As long as those cones of moisture overlap enough, all is well.
Over-doing it doesn't hurt, either. If you got those slow drppers, 3-4 per pot is probably fine. Those don't look like large pots.
stop rationalizing anythign due to "all 9 are the same on everthing" because the moment you start growing that isn't true and probably wasn't true to start. All sorts of things can be different that you have no idea about. It's smart to try to do things the same, that eliminates problems that we can control. Accept that some things are not in your control.
The way you are irrigating might be the cause of the inconsistencies.. could be your formula too.
with living soil, assuming by first diary, it's nearly impossible to give suggestions. depends on how it is built and if it is built well. if you see problems, it's lacking. adjust and hope you solve that problem next cycle until you get to no-till, if that's the goal.
Can't get a good look at symptoms, but anyone can compare those to a leaf symptom chart and make some common sense conclusions.
if you are in soilless/hydro now, this is a good starting point in vege phase.
PPMs
N 120-130
P 40-60
K 180ish
Ca 100+
Mg 75ish
S 100ish, maybe more.
Your tap water will require some adjustments. So will your VPD if it differes from mine, etc... This is a good starting point that will require minimal adjustments to make it work for your environment and 95% of any plants you throw at it. reduce N to 100ish 3-4 weeks into flower as stem elongation and leaf growth abates.
This fairly low concentration is fine for young plants too. This info doesn't apply well to soil/living soil context. Those fertilizers are not all 100% plant ready and 100% soluble to start. They require intermediary steps by microbes to make it plant available. this impacts how much you may need to give. Plus, you have slow release fertilizers in the soil that need to be accounted for.