That will depend on what the repeat for the wallpaper is. If it is straight hang it won't matter, but if there is pattern it will have to be matched up according to the repeat. It should say on the roll what the repeat is usually in inches. You could lay it out tonight if you have a space large enough to lay at least two pieces at a time to match your pattern. It would be a real drag to cut it all tonight to find out tomorrow that the pattern doesn't match.

Linda

Watch out...is there a repeat in the pattern?  You know....if the wallpaper has a fluffy dog every 21" and you want all of the fluffy dogs to line up from flat to flat then you sure need to leave a lot more than 4"-6" over the 8'-0".  If the pattern is little rosebuds it is easier.  I assume that your wallpaper is not as wide as your flats so you have to match up the pattern on at least one seam down the middle of each flat.  Better to cut the paper as you are applying it.  If you do screw up and cut all of the paper too short you can make horizontal seams...just make sure they are glued down well ( use a seam adhesive and a hard seam roller) and no one in the audience will ever see the seam.  I would use my time before " wallpaper night" making sure that all of the surfaces are clean, smooth, dry etc. and that there are plenty of supplies ready for your work party tomorrow.  Whay can't you start it tonight?  In my experience wallpaper is never " slap it up and be done"....it manages to slap me around instead.  Most important tool?  Sharp razors and clean sponges....good luck.