Just sleeved my copy. Go with the Fantasy Flight green package.
Great. I have a couple of the Fantasy Flight green packs that I bought by accident once. I'll try them and if they're the right size I'll buy the others. The Fantasy Flight sleeves are available locally, the Mayday ones I have to order.
I believe they are regular playing cards. You'll need different backs for the different political years.
The Fantasy Flight sleeves are clear so I won't have any trouble with the different backs.
Now to work on some tuckboxes.