So you mostly play on light oil to desert conditions?
Do you ever play on heavy oil?
There's a few factors you ahve to consider when you're building an arsenal.
What oil pattern do you play the most on, what kind of bowler are you, style and such.
If you're a stroker/straight player, then an agressive ball will help a lot.
If you're a cranker, then an agressive ball might be hard to control.
If you play on heavy oil, then you should get a heavy oil ball.
But since you play on desert, you should get a light oil ball, like Loco Pearl.
Since you want to try Hammer now:
Scandal or Bad Intentions Hybrid for heavy oil
Viral Solid or Arson Solid for medium or lower.
And the Blue or Burgundy for desert.
So since you're saying you play on little oil most, get a medium oil ball and one of the lower performance balls just in case the medium oil ball becomes too agressive.