SD cards write speed : SanDIsk

[iND]

As a canon user I have a collection of Compact Flash cards that should last me a while.
But with the SD slot in the 5DIII I am looking at the SanDisk SD cards for the second slot and wondering about the write speed:

ExtremePro 95MB/s
Extreme 45MB/s
Ultra 30MB/s


What speed does the 5DIII write:

I have always been a fan of using smaller MB cards and a lot of them.
The reason is if a card get corrupt or loose one I have not lost the entire day.
I change about every 500. ( I shoot 3000+ at a wedding).
I plan on shooting and saving the images to both cards as an added security.

I have always used SanDisk in my Canons and really not thinking of changing unless better quality exists.

Thank you