Always Use All Grommets
One of the more valuable lessons we learned from our wind tunnel testing was the importance of using all of the grommet spaces we provide when installing banners to any surface. Regardless of whether you are installing your banners indoors or outdoors, we cannot stress enough that using all grommet holes for securing the installation will ensure your banner is safer and more resistant to tearing.
Many banner installation recommendations make the argument that using only the four cornered grommet holes are enough for a secure and safe install. Not only is this an inaccurate recommendation, using only the corner grommets lends itself to more easily over stressing your banner. Using only corner grommets to install your banners is much more difficult to eliminate wrinkles in your banner. Wrinkles affect your banner's presentation, but more importantly the wrinkles cause more of an uneven stress eventually allowing the banner to stretch in a manner that degregates its strength.
If you are hanging banners in a location, the first instinct that comes to mind is to fasten a banner directly from the grommets to two or more anchor points, making it difficult to apply fasteners to all grommets. However, if two ropes or cables are tied parallel onto the anchor points instead of your banner, you can fit your banner between the two ropes and easily tie your banner to the ropes using all the grommets. This process is a safer solution for suspending banners and make a better visual presentation for your printed message.
When using all of the grommets for an install, be sure to secure each grommet one after the other starting from one of the top corners and working your way across. Once the top is secured, be sure to repeat this process for the bottom. By securing each grommet, one by one, moving across your banner opposed to securing the four corners first, will ensure there is no sag in your banner between grommets.