treat it like soilless, because that's essentially what a light mix is... a nutrient charge meant to last ~2 weeks or so.
Anything 100% water soluble and plant available will do well. Something that provides a full diet since you don't have amended soil.
I'd also suggest switching to dry nutes. You can make concentrated stock solutions to minimize how often you need to dissolve it. Dry nutes last decadeS, so you can buy in bulk. Takes me 3 or 4 years to use a 25lb bag of calcium nitrate. Fertilizer should be one of your cheapest expenses.
j.r. peters jacks 321, cropsalt, megacrop, southern ag, masterblend et al .. all have decent "3-part" setups that will provide 100% of nutritional need. a 'base' product along with calcium nutrate and magnesium sulfate - the last 2 you can buy any cheap generic) Great thing about using cal nitrate is you will never need cal-mag again, lol. Never bought the stuff. Never needed it. I got a 8fl oz promotional bottle 5-6 years ago... completely sealed an unopened.
nutrition needs aren't really different for autos. i've used the same formula on each with similar results.