Your problem is easily adressed.
Your only growwing in one gallon dwc, So if you mix up 1/4 - 1/2 strength nutes you should be fine. if you had a TDS pen you could determine if you nutrient solution was getting stronger or weaker as you water levels droped. you want them to remain the same so the plant is using watter and nutrients at the same ratio. that way you dont have to worrie about burning your plants or underfeeding them when water levels get low.
You really cant underutilized your plants, so i would start with 1/4 solution, see how it goes and then make your way to half strength. If you dont have a TDS pen then make sure you check the ends of your leaves for signs of burning after introducing new nutrients.
a lot of guys try to get their PPM to be as close to burning as possible(1500-2000). But truth be told this is a pain in the ass. you do get slightly more yeild, but personally i think the risk of burning outweighs that benefit. because if you burn your plants for 1-2 days and they recover for 1-2 weeks, you just lost like 30% of yield anyways. if you dont have a resovoir and are only using one gallon bucket.
for LED's dont mess with lucas formula, just be sure to replace with fresh mixture every few days, and start at low strength.