Sounds like your doing a good job of trying to be on top of things. Yeah id back the light off a little to like 750-800 without C02, but like I said I don't see any bleaching, you might be able to leave it like triplefast said and see if just the feed helps. A common practice for watering soil is to water well with 10-20% runoff just to make sure the root ball is well soaked. Then let it dry back to where its like a dryish damp sponge, you don't want it dry dry. When the ocean soil dries out in tends to become a little hydrophobic, so sometimes water will run out the side of the pots or run through little channels, not saturating everything evenly, so I always opt for slow watering and runoff. Also if your feeding with liquid nutrients its a good idea to get some run off each time you water or feed to avoid build up. Based on pictures and info, Id guess you should be watering every other day or every 2-3 days right now. Week 5 they can take the most food and water.
As far as watering, you'll want to alternate between plain r/o water with just a little calmag and your main nutrient mix. So if you fed last water, don't feed next water. However, when you transplant into a fresh pot of soil you have food, so you just have the same watering every time, which is 1ml botanicare calmag, dash of great white, 2ml full power, and 1ml FF big bloom per gallon in R/O water. Use some silica and trinity or other carb at 1ml/gal once every week or two to give microbes a boost and strengthen plants. This gives you a nice low EC tea that helps the soil feed your plant and feeds your plant actively a little too. Keep your pH between 6.3-6.8 and let it drift a little in between there, don't do same pH every time. Naturally the nutrient mix is usually the lower pH water and the plain calmag water is the higher pH water.
Once the plants start to look like they need food, which is a lime green look, some yellowing leaves, you'll start to add in either your grow or your bloom to the above mix. There are other additives you can add too. But basically thats like 2-3 weeks after planting into a good bag soil, and you want to catch it as soon as you can, right when they seem to not look perfect anymore.
Sounds like you don't have an EC meter, you should get one for mixing nutes to be safe. But right now I would feed with 2ml calmag, 5ml tiger bloom, and 15ml big bloom if thats all you have at a pH of 6.5-6.8. The pH is on the higher side because you've been watering with 6.0 and we want to counter that for nutrient availability. Water well and get some good runoff. We want to give them a lot of food to pull them out of the deficiency to try to save the yield a little. Then next water do just the plain calmag water and so on. Stop calmag at week 7, stop all food week 8. Boost to 6-8ml tiger bloom if you think they can take it after watching them respond to the 5ml feed. You shouldn't need to flush because your plain calmag water to runoff flushes them a little each time and you get runoff from nutrient mix too and were not feeding a crazy hot mix.
Personally I don't think you need the extra perlite in the soil, all soils dry out from the outside in, top down, especially in fabric pots. And honestly, its rather hard to overwater a plant in a fabric pot with a good soil unless you really drown it or your environment is very off. And overwatering doesn't come from how much you put through per say, its more about if you keep it soggy wet consistently. I have done the same thing with the same idea as you, but what ends up happening is that your starting to fill more of your pot volume with perlite, which is an inert medium vs soil that has food. So you can end up needing to treat it more like a soilless mix and feed with more liquids more often, which is fine, its just a different direction then an amended soil that mostly feeds the plant for you. We can talk about amended soils if you want. I would recommend switching over to roots organic original, but ocean is still good. You could do side by side too. Maybe just add some worm castings and a bag of FF planting mix to that soil you mixed up to compensate for the pearlite, or just run it, maybe you'll like it.