Some questions about using wall graphic material

[gabagoo]

I have a customer who wants a wall graphic 6' x 7' - I plan on using Avery 2611 to print on. If I do a seam would you apply them with an overlap or butt them up, or do the overlap and like with wallpaper cut between the 2 and remove the excess? What about shrinkage

 

[CanuckSigns]

1" overlap is best, that material shrinks a bunch