Anyone have suggestions on replacing battens?

I have Bluestreak battens and have 2 that have splintered.

My question(s) are:

* Should I replace ALL battens or just the two?
* Do I go back to the sail manufacturer (Red Head) to get the right draft cut into the battens?
* Buy them directly from Permex Products or a distributor?
* Perhaps there is a different batten manufacturer that others would recommend?

What about batten strength for cat vs sloop?

I think I read in an "ancient" post about putting x-stiff battens in the top two batten pockets for cat rigged sailing.