drying pattern does look fishy.. wet in middle but lots of dryness around the edges beyond normal dryback pattern would cause.
1) fully saturate (10% runoff in soilless, minimum)
2) wait for appropriate dryback (loss of water weight is best indicator or depth of dryness up top) and repeat.
if not doing that, you are doing it wrong, and it could be part of the problem. Media constitution looks fine - enough of perlite it seems for aeration/oxygenation. it's nearly impossible to overwater a properly constituted medium. Full saturation is not overwatering. it's the correct way to water. (10% runoff waste minimum, if soilless, too)
If watering habits are fine, try moving that plant to the corner rather than the middle... maybe it's just getting a tad bit too much light, but that visible drying pattern looks like bad watering habits to me. some dry pockets or high concentrations of nutrients buildt up in areas where the water ebbed and flow in weird ways due to odd watering habits etc etc... it's something that doesn't cause problems initially but over time can develop into a big problem.
i regularly run 8 plants at at ime and rarely does one require anything unique to remain healthy. Even the ones that do exhibit some minimal symtpoms never require individual attention. I have hand-watered a mature plant once in the last 4 years. It was a humboldt plant, by chance. Even that one I probably could have powered through and just accepted the slight deficiency symptoms and still finish okay. A good formula can work well for 90-95% of plants at least.