Your windscreen is probably levan or perspex. This is very easy to scratch
and the dust on the screen would soon turn the swept area to white with
scratches.

You could have a small panel of glass, probably some sort of laminated super
duper automotive windscreen glass but you may well want it mounted in front
of your bird resistant lexan.......

If you wanted a system with redundancy for when the power fails, Series 1
and 2 Landrovers had a single wiper motor and gearbox that mounts inside the
windscreen and can be manually operated when the electrics fail. Of course,
being manufactured by "The Prince Of Darkness", the Lucas electric motors
needed this feature.

They are not all that bad, both of them on my 1964 2A shorty still work,
even though they spend most of their life out in the paddock.

Hope this helps,
Peter