It’s true that when moving most of the rain heads over the screen, but the airflow then brings the wet in from behind 9hence the inside of the windscreen gets wet). This can be overcome quite well by fitting a polycarbonate wind deflector to the roll bar(s). I’ve heard it said by a competent source that it you make this deflector was wide as you can (whilst still being able to get the hood on if you have one) it can really reduce road noise too. In addition to this I have recently made some polycarbonate side windows (large ones)that reduce buffeting and road noise and attach between the small side screens and the windscreen frame. If left outside, a tonneau keeps most of the wet out of it and if theres’a zip front to back along the centre line you can open the drivers side and drive with the other half in situ.