I recently rode in a 800 trail with the 1/2 CFMOTO in very dusty logging road conditions. This windshield has a pretty good kick on the top lip & it was mounted as low as possible. No roof or rear winder.
I've never been so fricken dusty including the entire cab
the air space behind the front 1/2 winder was dead. So the vortex was full on behind it, if I put my hand out in front of the winder it was blocking a massive amount of wind
My suggestion to the owner was to start raising the windshield to get some air moving between the lower part & the cab. The amount of wind I could feel with my hand suggested you might be able to tune down the Vortex while getting some air flow in the cab.
Another separate comment was from the owners wife with the half windshield, the water ran off the roof & she was not happy. This is different unit.