Its easy to say that Pinnacle Souveran is the best carnuba we carry, and simply a great topper. But as with anything, its price point, and user preference comes into play. You could not do wrong with Pinnacle Sig Series, DP Max Wax, P21S, or Nattys Blue on your dark wonder.
As for Klasse SG, I think most would suggest using it prior to Wolfgang as Klasse is an acrylic sealant, while Wolfgang is a poly-sealant and glossier. Klasse SG is a pain to get off properly (hint: use small fine mist spray bottle) but is nearly bulletproof once cured. It also is a little sterile compared to some of the newer sealants.