I would definitely agree on getting the Venom Shock as the benchmark ball.

For the lighter side, I would suggest the Freestyle over the Tag.  Much better predictability.  Tag was hit or miss.

For something above the Venom Shock I would lean towards the Trident over Jackal Ghost.  The Ghost would be great if you are expecting true heavy oil and flatter than THS.  However, if you are talking about heavier THS, the Trident I feel would be better suited for when you have to go away from the pocket.

I didn't recommend any of the medium oil equipment only because the Venom Shock is stronger than expected.  I don't see more than maybe 2-3 boards difference between it and the GT or Chronic Paranoia.  If you are going to limit yourself to 3 balls, and you want to cover the widest range of conditions, then the Trident-Shock-Freestyle will do that for you.

Some other pieces that could be interesting:

The new United Revolt sounds interesting, but not sure yet of the shape.  Motiv has the Revolt Havoc and Primal Fear in that range and the gap between them is kinda large.  I expect the United to fit between but rumor has it it might be closer to the Fear than the Havoc.  If it is between the two, it could be a great replacement to the Trident if you don't think you will see heavier shots.  The Vanquish core is pretty nice.

The Venom Cobra could be a replacement for the Freestyle if you don't see real burned or short conditions.  It is a couple of boards weaker than the Shock but definitely a different shape.  The Shock can be pretty early OOB so using the Cobra may be able to keep you in the same area of the lane and help when you get too deep with the Shock.

Chronic Paranoia can replace the Shock, but the Shock is so good.  The Chronic is just a tad stronger but also not as early.  Depending on the look you like, the Chronic may be a better fit.