Consider these which go directly on the battery. I have them:
Fuse Block Terminal Post
Also here is an example inline fuse. They say they go down to 30A.
MIDI® / AMI® Fuses
The way to think about fuses is that they protect the wiring. Technically every branch of wiring should have a fuse to protect it sized no higher than the maximum the wiring can safely carry. This protects the wiring from burning up in a short (and it doesn't hurt to go lower if you know your loads don't need it). Ideally you'll have a fuse at the battery sized for the starting load, then a fuse for the panel sized for the panel load.