Super Snowboard or Maple Karstan?

Considering they are still only lvl 51, its low dex on the idea of end game.

As for what to use, if you have both, use the SSB for normal training, and the Karstan when you are unable to hit higher lvled monsters.

Hate to break it to you, but anything above ~20-30 DEX is regular DEX. 5x DEX is bordering on high.