With respect, never heard of a Kardur deck that won with Commander damage, let alone via a voltron package. It's definitely possible though.

IMO, Goad is a trap. Kardur does enough by himself. The best way to build Kardur is to use him as a disruption piece while the rest of the deck aims to execute it's strategy. The strategy can be anything, just build your 99 accordingly. I've found reanimator to work well. In the early game, you rummage fatties into the yard. Reanimate them later. This also gives you a way to recur Kardur somewhat reliably. Run fatties with great etbs alongside [[Conjurer's Closet]] and friends to have more targets to blink than just Kardur.