2 gauge is extreme overkill. Have you seen that wire, huge!!

4 gauge is plenty.

As to the Daisy Chain VS Distribution Block, it won't matter as long as everything is connected well. These ground runs are so short (ie. <5 ft.) so it shouldn't matter at all.

Jung

P.S. I spent a lot of time perfecting my battery setup, with good grounds, great cable, blah blah, and then my Optima Battery went bad... ugh...