Post a link to your rack rather than a picture. Modular Grid will reference a picture of your rack but then I can just click it and take a deeper look at your modules.
Here is your primary issue. Your case is too small. That's the beginning and the end of your problems. Everything else is just a bandage at this point. You're going to go around and around trying to make choices and compromises when one of the cheapest things that you can do is just get a bigger case. A Mantis (for example) has 208HP of space and is under $350.
Everyone tries to build their modular battleship in a bathtub and they run into this problem over and over and over again. Skiffs and small racks are NOT for beginner systems. It's a terrible place to try and save money and you f--- yourself over every.single.time.
Sell the old case. Buy a bigger one.