I have been in the painting and wallpapering buisness for 22 years,and one thing I can tell you without a doubt is that 99% of the people working in these stores have little or no knowledge of the products they sell or the level of expertise of the contractors they deal with. Even though their always quick to hand out advice. Any paper hanger worth his salt should have no problem furnishing you with a minimum of 5 or 6 references that you can contact. That is the only way to insure that the contracter you are talking to knows his stuff.