The fewer bristles touching the glass, the easier it is to rinse.
I have found that the easiest way of rinsing is to take the weight OFF the brush-head and let it 'scim' across the surface of the glass while you move it from side to side. In other words - only the uppermost bristles are touching the glass.
Or, as you move the brush from left to right, lift the left side of the brush off the glass - and when moving right to left, lift the right side of the brush off the glass. (Acknowledgement to NWH)
It is important though, to thoroughly wet the complete surface of the glass (not easy to see, sometimes, from down on the ground) before commencing to rinse - using plenty of water along the top edge and in the corners.
Mike