Bigcube help

[Zbox95]

Hi, I'v started solving bigcubes alot more since I finished leraning full PLL.
But I always run into the same problem over and over.
The last two centers are always TERRIBLY slow for me and I don't get how all the fast guys do them so fast, and they almost always use various r and U moves.
If anyone knows a good website or just have some general tips that would be great and much appreciated!

PS. Some edgepairing tips wouldn't hurt, but not really needed.

 

[Selkie]

Bit of belated advise and not sure if you still need it but both the 4x4 and 5x5 PDFs on this site page give algs for centers and edge pairing. Might be of some use...

http://www.kungfoomanchu.com/#bigcubes