Up until last month I would always change my brush angle for roof lights to about 90 degrees to the glass and often still do to get height over the roof edge.
However I have now been trying a different approach when there are roof lights on a single storey extension and typically bedroom windows above.
Instead of doing the bedroom windows, collapsing the pole and adjusting the brush head to 90 degrees and re extending, I set the brush for the bedroom windows, maybe slightly more angled than normal and then if the roof edge allows, use it for the roof lights.
I was concerned that the jets might bring grit or muck down from the top edge but generally it seems ok and saves me a pole collapse and brush adjustment. Probably saving about 30 seconds and some pole wear.
Have I got to the point of diminishing returns?
How do you do roof lights on regular work?