Which is better for improving dribbling and shooting?

[hateraid]

Using a slippery ball when warming up and shooting around then playing with a decent game ball or using the same ball for both?

I've always used a slippery ball when shooting around. Then when moving to the game ball I get a much better grip and release. I've always been one of the top 2 or 3 shooters no matter where I play.
What do you guys do?
Any other warmup tips?

[FatComputerNerd]

They say Kyrie used to practice dribbling with the ball in a plastic bag to make it more difficult.