I struggled for a month to figure out the best configuration for the Infinity 6” inline fan and the GF. I have a sensitive nose so I couldn’t stand any burning smell. With the current set up, I have been cutting with 2 GFs for the entire day without any smell in the room. I have came up with several 3D print adapters for my best configuration. They are: GF exhaust port extension, 4” to 6” adapter, 6” mounting adapter. I share it here and hope it will help someone in the process of installing the Infinity 6” inline fan. The 3D files can be found here: https://www.thingiverse.com/thing:4362064/files
My best configuration in order: GF + exhaust extension + 4” duct + 4”to 6” adapters + 6” Infinity Inline Fan + 6” Mounting adapter + Window.
I bought the fan and duct from amazon: