I rinse off the glass but only by a few millimeters. If the tips should touch a little it doesn't seem to matter. I often wonder if there is that much need to remove so many bristles on a brush for the jets? Gardiners take out six sets of bristles. (but then Alex knows what he's doing by now)
We remove six sets of bristles (3 on each side) on the Bentley brush and the sill brush only. On the rest of the Vikan range we remove no bristles apart from the swivel brush where we remove four. The reason for removing bristles is purely to allow a clear line of sight for the jet. As the bristles on the Bentley are quite angled, this means needing to remove three sets of bristles each side.
Rinsing on, rinsing off - both can work but it's obvious which will have the higher success rate. With our monofilament prototype brushes, I can get away with rinsing on when doing higher work (notice the phrase 'get away with'). In my tests, I've always found that rinsing off will provide a quicker movement of particles. However, when dealing with larger bits on the glass, rinsing on, ie, using the brush to pull the bits off, can be quicker. Experiment and use each technique wisely!