Replacing shafts on a set of Cleveland CG7 Black Pearls?

[Balto]

Thinking about picking up a set of Used Cleveland CG7 Black Pearls but will need to switch out shafts to a stiff shaft. I'm thinking about the Project X 6.0 Flighted (or the 6.5s). Been looking on Ebay and Golf Forums for Used ones.

The question I have is about the Tip? Does anyone know if I need Parallel or Tapered Tips? OR does it matter with the Cleveland CG7 Black Pearls?

Also, my 6 iron SS is about 90 and Mizuno suggest X100(Soft Stepped). Can anyone that has a set of the CG7 BPs compare Clevelands "Standard" Flight Speed Shafts to say Dynamic Gold and Project X shafts? I know each companies stiff is probably another companies Reg flex and if anyone has hit both the Stiff and Reg Cleveland Flight Speed shafts do you think the Reg flex would play more on the stiff side and MIGHT work fine with my Swing Speed?

Thanks in advance everyone I'm still trying to learn all about Shafts and so on