Which came first, the chicken or the egg? In my case, the charge controller or DC shut off switch

Wow. It's going to take a while for me to peruse this information and let it soak in. I know that sounds silly to anyone who is 'in tune' with this information, but my head starts to spin as soon as I try to decipher it. But thank you PW and LH2 for all of this good stuff and the pics, too.

Per my inability to register electrical theory easily, I often think about another problem I've had before. When I was in my mid 20's back in the early 80's my younger brother and I moved to Texas to find work, since there was nothing in Missouri. We found jobs at Dow Chemical in Freeport, TX at the infamous "Red Planet" in the plant where catalyst pills for Dow's styrene (styrafoam) were produced. It was basically an automated plant that created those pills out of a slurry of iron oxide and a lot of other ingredients, but there was a process of starting up the system's kiln, augers, etc. which was done on a huge board with more lights and switches than I could count. It was a simple (to everyone else, including my brother) start up system that had to be done exactly right, or it would shut everything down. I was just flabbergasted by how I could not get it right, no matter what I did. And I consider myself an intelligent person! But that "simple" process haunted me the whole time I worked at that nasty place. I would literally sweat red for days at Surfside Beach or the pool when I was off. Anyway, that's about when I realized that I am not wired for some things. Once I get something down, I'm fine. But it's just the idea that I can't grasp a thing when it's right in front of me sometimes. Like riding a bike, once your over the hump you wonder what kept you from 'getting it' before.

Mike, you've helped me before and you are correct, we've discussed the importance of over powering breakers and the problems with going over the limits by different effects (cold, brightness, etc.), and the damage it can do on undersized equipment. That I can understand. I'm just trying to figure out the elements of the flow path and how it is affected by everything else in the system, along with my (still) difficulty in completely understanding electrical math.

I know this may not help, but for the sake of clarity of what I'm working with, I'm putting a couple of pics of what I have and what I intend to end up with on the wall. The first pic is the ad for what I bought years back in anticipation of going off grid, and a second pic of what mine will end up being, which Robin Gudgel use to own.. Oddly enough, even though it may be considered "antiquated" to some, it was a system that he (Robin) had in his early days. Unfortunately, in order to store it I had to dismantle the systems parts, so I can't give you any good pics (until I dig them out of a box I've stored somewhere) of the original power board wiring. Right now all the equipment is layed out on a big table. But I will get back here as soon as I've studied your replies. Sometimes I have to laugh at myself. I can get out a blueprint of a power house, a car plant, a brewery, a bridge- and know exactly what needs done from A-Z, but when I do the same with this system, it's like I've never seen a wire before. But that's what I'm on this forum for. A way out of my fog.