What size/type fuse to go from Alt to fuse block in Ls swap?

[cpd004]

I'd like to put some type of fuse in line between my alternator and the fuse panel. I'm not sure what size fuse and what type would be best. It's an Ls3 in a 71 Firebird that had a Painless muscle car harness put it in at some point. I'd also like to be able to pull power from one side of this fuse for the fan's. The fan wiring has it's own fuses in line. Any suggestions would be appreciated.