how many fuses and where?

I am trying atm to purchase the last couple items for my setup.  I dont have alot of time so dont want to get into the specifics of what I have all you should need to know is that I will have two optima red tops in the trunk, no battery under the hood.  With a high output alternator.

My question is this, how many 300 amp fuses will I need to connect the alternator and batteries together? 

So far I can see that I should for safety sake have one off the alternator and then another at the other end of the wire at the battery.

Then another one from the fuse block under the hood to the battery which will have a 2nd.

what about battery to battery?  They will be side by side so I assume that I need no fuse.  Then from the batteries to the amps?  The wire will probably be longer that 18 inches but they will go directly into the amps, which are fused, (I know that has nothing to do with the 300 amp fuses) Do I still need a fuse off each of those 2 wires?

Lastly one more 0 gauge wire to a distro block for my 4 channel and caps (I already have them so im using them lol) Another there?

To sum it up, do I need all these 300 amp fuses?  Am I missing any?  Do I need to run the alternator directly to the battery or can I run it to the old battery location, combine with fuse block wire and then run a wire down?

Lastly I was looking at these...and concerns, should I be spending more money on these blocks?  Maybe waterproof ones for under the hood?

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if I did that wrong it is ebay item number - 140204658535

Thanks

I wanted optima red tops and even the small ones are too big for the stock battery placement under the hood.  It just wont fit so I have to have them in the back. 

Also as you say they are bottom of the barrel...any suggestions on where to get better ones online or what brands to look for? / what material they should be made from / coated in?

Here's some of what you need to know to figure out fusing:  every power wire needs a fuse rated for that wire, close to the source (of power). 

examples:  If a wire goes from battery to amplifer, the source of power is the battery.  If a wire goes from one battery to another battery, then there are two sources so each end of that wire gets a fuse.  From battery to alternator, look at it this way:  the battery stores amperage while the alternator produces it only when it's running.  In a catastrophic event it is the unleashing of stored battery energy that is so dangerous.  Fuse at the battery end.  For the battery to battery in your description, where the batteries are side by side:  a few inches of wire in that situation needn't be fused because a collision will crash into those batteries at the same time it damages the wire.