A diagram can be a good thing, however, I feel like it is a little flawed. The Absolut Curve is in no way a heavy oil ball, nor do I feel like there is a ball that is truly a "Heavy oil" category ball.
Medium-Heavy: Cold Blood, First Blood, Absolut Hook, Deadly Aim, BW Assassin, BW Legend, AMP, Arson, Rachet, Purple Taboo
Medium: Absolut Curve, Absolut Flip, AMP UP, Spike, Arson Hybrid, Jet Black Taboo
Medium-Light: Arson Pearl, Arson Low-Flare, Spike Blue/Black, Wrench, Chalk, Nails, Vibes
Light: Blue Hammer, Polyester covers.
Upon looking at everything you can see they have too many damn balls that aren't retired yet. Me personally, I think they should condense and makes things easier on the public.
Med-Heavy: Gas Mask (Widow/Taboo Series) and/or Aims
Med: Absolut or Arson series pick 1
Med-Light: Nasty core (Spike series) and/or Vibes/Vibe Replacement
Light: Urethane/Polyester