MAD ELECTRICAL?

The original wires Red and Black are both 12 gauge to the Amp gauge. I am looking at both ways of doing it. The first way is I am just going up to a 10 gauge wire from the Alternator to the starter relay as MAD shows. The other would be a 10 gauge with an inline fuse as you show. What do you think, and what AMP fuse? Thanks a lot...