How to deploy ML to other cards:
Just install it on each card as you did with the first.
How to preserve configuration
In the FAQ of the Magic Lantern site you can look up the following question:
"How do I save the gain/zebra/etc configuration?"
There it states that you can generate a
magiclantern.cfg from the Debug menu in ML.
.cfg file can be copied to the other cards which have ML installed on them.
I have tried this with my Canon 550D and it seemed to work. It remembered stuff as Global Draw and Audio setup. According to the FAQ you can also edit the cfg file in a text editor. Here you can find an example of a saved configuration file from ML 0.1.6 (look for the heading "Saved Configuration Files")