Neptunes is good to go. You can honestly just use that alone if you choose and you'll do great.
If you want to use another source look for a good tomato fertilizer. I have used dr earths organic tomato fertilizer and my chilis love it. It contains fish bone meal, feather meal, kelp meal...
I really like what you have going on there solid. You've inspired me to try this next season. Not trying to hijack this thread but... can you elaborate on your technique? Does the braid hold by itself?Do the plants require any direction training or do they just naturally point away from each other?
I purchased a Carolina reaper seed collection from Peppersbymail not too long ago. I received at least 20 of the yellow, chocolate , peach and red varieties for only 10$ . Germination rates were stellar. Even got bonus seeds (btr and red bhutlah). 120 seeds in total.
We need a deeper understanding of your growing conditions . The soil being used in the container, feed schedule, type of fertilizers etc..will help to identify the problem so we can provide you an accurate solution.
You could stack the garden pot (with the pepper plant) into another empty garden pot and fill the void with straw or leaves . Also make sure to apply plenty of mulch around your plants.
Your plants look good. The bottom picture looks like it could need some calcium. That being said a little salt won't hurt them. https://www.worldofchillies.com/growing_chillies/growing-tips/chilli-plant-nutrient-guide/files/stacks-image-459d210.jpg
Looks like sun scald to me. Those first leaves most likely weren't use to the suns rays. The new growth should be more resistant to the harsh summer sun. If it continues to happen you should consider 40% shade cloth.
Sure looks like edema. You can't really "water less" with DWC but like honey badger said you need to get proper air circulation drops decrease the humidity around the peppers. This will prevent edema from forming on new growth.
It's hard to decipher the issue from your pictures.. but it's possible the "scaling" is edema. If that's the case make sure to have a fan near your peppers to give them circulating air. It won't remove the edema that's already present but the new growth should be good.
I was interested in purchasing several rocoto plants. Can they be grown in the west Texas heat? Summers down here can be hot (100+) for weeks at a time.