Depends on the oil.
Heavy: An Awesome Revs or an Awesome Hook, depending on how heavy "heavy" is for you.
Mediums: Finish or Flip. For the oilier side of medium, a Rev's drilled modestly (not weak, but modest) should be fine and cover all of medium and some into the heavier stuff.
Light: Sahara the whole way.
Looking at what you've got in your profile, I'd say go for a Revs or a Hook to fit above your TNV for heavier stuff. You've got the mediums completely covered from all angles with your T-Road, Spit Fire, and Vibe (depending on how they're drilled).
Ideally, in my opinion (I played that up-the-boards line for a long time), a good arsenal to take with you would be three balls: A medium-heavy, a medium, and a light/spare. If you know what you're running into, then you can vary that quite easily (medium-heavy, medium-heavy with a different drilling, spare, etc). If you wanted something for true floods though, you can't go wrong trying to get your hands on a Total Shock and Awe. But unless you see some serious soup, don't bother.
Hope this helps.
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