If you are a beginner and counting is the only technique you deal with, CVBJ and CVCX (for doing simulations of a counting system with fixed playing strategy, i.e. fixed indexes for deviating from Basic Strategy, in order to create an optimal betting strategy for various counts) should be sufficient.
CVData is for more advanced stuff like creating optimal indexes for a specific counting system, hole carding, next carding etc. CVShuffle is for shuffle tracking (zone tracking and ace sequencing), which are more sophisticated and complex techniques going beyond counting.
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