Due to the size, it is recommended to split into 2 flyscreen instead of 1. Smaller screens are easier to install & operate.
Use centre vertical frame to split and make sure there are no gaps between grille & window (refer to image below)
To install on grilles, make sure there are no gaps where insects can still crawl in from. For 3 panels grilles, can install either 1 piece or 2 pieces.