Need to know if i am doing my wiring properly.
 

I have 210amp alternator and a kinetik hc 1800 under my hood. I did the big 3 upgrade using 4/0 welding wire, connected my ground from frame to engine and to battery negative post, and I run a wire from my alternator to battery positive post. I have two Kinetik hc3800 in my trunk which i connected parallel, I run a wire from the front battery positive post to the rear battery positive and I run a wire from the alternator to the rear battery positive post. My question is what amperage should I fuse it at or should I use breakers? And which wires should I protect? I also run a wire from front battery negative post to rear negative post using all 4/0 welding wire. I know the wire is a bit over kill but fell off a truck lol.

I have a soundstream xxx6500 and a Lightning Audio 50 Farad Carbon Capacitor which i'll connect together from the rear batteries. If I am fusing the connections from the front to the rear do I have to still fuse the rear batteries to the capacitor that is connected to the amp? This amp will be connected to my two 2010 Orions 15.4 hcca subs.
I also have a REF4.920 - Soundstream 4 Ch. 920 Watt RMS Class A/B Reference Series Power Amplifier which i'll be connect to the rear batteries

Sorry I can't keep it short, just want to make sure i'm connecting my setup right. THANKS FOR YOUR TIME!

If you have the big three, you should not need a capacitor.

That's all the input i can give.