Fusing between alternator and battery.

I have a '65 Dodge Dart that came with the standard factory wiring through the fire wall which is notorious for being substandard for even stock, and could be a melt/fire hazard. I have installed a rebuilt 50 amp alt., new battery, and voltage regulator. I have only the factory lights and AM radio with no extra biggies planned on being put in. I already installed 4 inline maxi fuse holders, with 50 amp fuses, two near the alt. output and two connected near the pos. battery terminal. Both pairs of wires are 10 gauge and @ 5 feet from battery to alt. Unfortunately, after installation, I found out from the distributor that the wiring used in the fuse holders are made from CCA copper clad aluminum instead of all copper. Should I put in thirty amp fuses or leave the fifties in. Will the fuses melt first or the wiring even at only 5 feet? But, then again, the way they were made, packaged and delivered was with the 5O amp fuses and the ten gauge CCA wiring. I know my ammeter will be off, but I intend on getting a volt meter. Thanks ahead for any advice.