The most noticeable issue for any paper hanger, is when the pattern runs off at ceiling or dado level,I use a smoother or spatula ,that is a little thicker for trimming corners,found it helps with bad corners,a good hanger is like a magician,slight of hand tricks the eye,wallpaper stretches and shrinks,laser levels have made life a-lot easier than the days of striking chalk lines,👍🏻

If I may add somethings which I believe may help minimize the chance of NOT getting paid: 1) have an open conversation up front before or very close the the start of the project and note, with the customer possible issues. 2) before starting- take pictures of the project area that show wall, floor, ceiling or other types of damage or potential issues such as popped drywall screws, paint on the floor, chipped furniture or broken/cracked wall decor/fixtures, etc. 3) damage to or imperfections in the wallpaper itself before hanging the sheet. Take a quick photo of it pre-paste, if possible. 4) work in a clean, safe, conscientious, & courteous manner.

I notice you are papering onto a textured wall. Does that create any other issues? Like the needing extra glue for the paper to adhere or air bubbles?