I personally wouldn't touch anything other than 'A' frame ladders for window cleaning. Much safer on uneven ground and a lot less climbs per day.
HOWS THAT WORK THEN
Hi, with an open top ladder you can only generally put it on the window sill resulting in you having to stretch up on a deep window. With the A frames you can place the ladder on the sill, half way up, at the side etc. On a wide window frame you can put the A frame in the middle strut& clean all in one movement. there is no stretching with an A frame as you place the ladder generally half or three quarter up the window frame.
See my post on "HALF A DAYS WORK" You will see ladders in photos.
Just imagin that the railings were no there, a long strech from the window sill to clean the tops.
Kevin WINDOLENE.
Kevin WINDOLENE.