You may wish to figure out the right size fusible link. They tend to be more tolerant of short term overloads like when charging up a dead battery. Also, just being a short piece of moderately undersized wire they can be a lot cheaper, and the spare is much more durable than any fuse. Another thing is you never want the alternator to become disconnected from the battery when it is outputting current. When that happens, many alternators die permanently.
The fusible link between the alternator and battery is there to protect the battery from discharging through a shorted alternator wire, like during an accident. It would take a set of near miracle circumstances for an alternator to damage a battery via over current. Over voltage situations, which is how alternators kill batteries, won't be stopped by a properly sized fuse.
Most fusible links are a 5 to 6 inches long at the battery end of the wire. If it blows, typically you can use a crimper and crimp the two ends together and get home, assuming the issue that caused the short is fixed. If the issue isn't fixed, it will just get hot, melt and blow again. When you hook it up again, you can feel the fusible link wire, and if it is getting hot you can disconnect. They are really very slow blow fuses. If a fusible link blows in a few seconds it was to small. It should take 10 to 20 seconds to heat up and blow.
Sizing. When I looked out for sizing a fusible link I found a few sites that said 4 AWG smaller than the wire size being protected, and 5 to 6 inches long. That way the voltage drop is minimal, and the fusible link will go first in catastrophic situations like dead shorts.
Sadly for us hobbiests, a spool of the right sized non flammable insulation wire made for fusible link use may cost as much or more than a fuse plus holder and then one will have 99' extra wire left over.
Quickly looking around I found this place,
MadElectrical Fusible Links, and others. They are selling fusible link kits that are 4 AWG smaller than the wire size they are to protect. At under $4 each plus shipping they are very reasonable too. Looks like you could substitute any size eye on the battery end. They recommend crimping, soldering, then covering with heat shrink tubing. Normally I'd say stay away from soldering, but in this case it will move the heat up and fuse spot to the middle portion of the link. Some places on Amazon Market Place sell fusible link wire in a number of different AWG sizes in 25 foot spools.
