[fct]

Just because the wire is good for 375A current, you don't have to use a fuse so big. It would be useful to know how much current you will actually expect in the most demanding scenario. The point of the fuse is to melt when there is a spike in the current so big that it can't be a result of normal usage (effectively a short). You don't want a fuse so big that it won't melt fast and reliably enough to protect your equipment. So for example if your amplifiers come with a total of 200amps of fuses and you intend to drive every single one of them at the maximum capacity at the lowest impedance, then use a 200 amp use on that wire. If you won't be driving them at the maximum capacity, then it's a good idea to use even lower fuse rating by making an educated guess concerning the approximate efficiency of each amplifier.

 

[fct]

That power wire length chart is a little too conservative. Take a look at various power wire calculators here:

WIRE

It may aid in calculations to know that Class D amps can be very efficient. 75-85% at 4ohms. 70-75% at 2ohms.