Good Idea about using Fan jets, and putting that idea into my head sounds good for con roofs and gutters. I always use pencil jets, but am looking for a brush that is good for Conny roofs, gutters and dirty frames. As you say, the gaps in the frames is the reason I am looking at this brush.
They are easy and quick to change on the SLX. Looking at the guide listed on the Gardeners website only rates this stiff brush it 1 tick for con roofs and Gutters. The Medium brushes range from 2 to 3 ticks for this. SO a little confused at their rating especially when they call this the Sill brush.