put the distro block by the battery, not in your trunk.
and fuse bat+ to amp + to your amp's fuse rating, not for the wire.
You fuse the Alt+ to bat+ based on wire rating, because you do not want the wire to catch fire.
You CAN fuse the bat+ to amp+ based on the wire rating.
Doing this will prevent the wire from catching fire.
But long before the wire catches fire, your amp will have been fried.
Because of this, you fuse your bat+ to amp+ based on your amp's rating or lower.
This will prevent your amp from being damaged.
This is a normal setup:
bat+ --fuse--------------fuse--amp+
This is a short circuit with a fuse rated for your amp
(xxshort circuitxx) bat+ ---xxfusexx---------------fuse--amp+
This is a short circuit with a fuse rated for your wire
(xxshort circuitxx) bat+ ---fuse---------------xxfusexx--amp+
As you can see, the fuse by your amp will protect it, but it is a close call.
Its safer to fuse for your amp farther away from the amp, as there are cases where the amp is damaged even when it has fuses, having another fuse is added insurance for your amp
this is a short circuit without a fuse