Any grade of Hardox will out perform pretty much anything else. (The number refers to its Brinell hardness value in HBW, using carbide ball indenter.)

It will depend on what thickness you want as harder grades don't come in sheets as thin as lower values; eg Hardox 500's minimum stock thickness is 4mm, where as Hardox 400 goes down to 2mm.

Hardox 400 will do you just fine. If you can get 500, 600 or Extreme then you are on a roll.