MSNL AK-47 First Attempt :)

You’re giving them too much light for their stage of life. That SF2000 should be anywhere from 18-24” away running roughly 50%. I don’t always trust the light manufacture settings and that is why I have an Apogee PAR meter to test my light output. You can achieve the same results with your phone downloading a PPFD App and testing it. Right now you want to be roughly 300-400 PPFD I hope this helps.

I wouldn't worry too much about the single and 3-fingered leaves. They often can be fugly and the plant will be perfectly fine more times than not. New growth looks fine to me. Bet the blemishes you see on those first 2 sets of leaves are not visible on new growth. There are hints of poor watering habits baed on how the top soil has dried. The basics: Water entire pot. A little runoff is fine to ensure it. Wait for top 1" to dry and repeat. How often you fertilize is a bit of personal proference. The higher concentration you mix it up at, the less often you fertigate. every other? every third? once a week? Just depends on your choices. I will say you'll probably get better results with lower concentraion / increased frequency, but YMMV. Don't deviate greatly from this. A good wet-dry cycle has numerous benefits. You can probably water a bit sooner than the top 1" drying, but early on, stick to this practice. How much perlite and similar in the soil will impact how frequently you can irrigate, too. How much water? As much as it takes. If you wait for the same 'dryback' when 1" of top soil is dry, it'll require a similar volume of water each time. So, you can learn to mix up only what you need to use on demand in short order. The loss of weight is easiest way to determine irrigation needs. Become familiar with the weight right at irrigation and when the top 1" is dry.