http://img212.i.us/my.php?image=p1010030wd5.jpgTaken from WFP Training Academy-
You dont need pressure, just enough flow for the job you are doing, I use between 1/3rd and 1/2 litre per min but can push out 2 litres. I found with ott sprays like that shown that the overspray caught the heads of the windows including bad paint and that I got lots of trouble after I had gone with runs all over the place.
I then went over to thro the brush sprays which I used for many years and with less flow, "pushed" the water wave right up to the top edge of the pane but not over the top onto the head.
I now use 4 jets aimed over the top of the brush to just go thro the bristle tips if I press a bit, but if I dont press I get really accurate rinsing.
Heres a pic
http://img481.i.us/my.php?image=p1010027wf1.jpg showing two yellow sprays on the left, notice the overspray and 2 green 1mm jets on the right. You could also mount either to go thro the brush if you wanted. I only do frames as an extra so the ott jets suit my style but maybe not yours. Also only just seen on left, yellow (leave caps on for sprays and green or blue with caps off for jets about£4 pack of 6. They simply lightly screw fit into 4mm irrigation hose
2. Buy some u shaped plastic channel drill 6mm holes thro both sides at the angle you require, push the 6mm pipe though and fit the jets. Fix to the brush head at the angle you require with 2 screws thro the base of the plastic angle. If you use bigger pipe use bigger channel. It makes it simpler when you want to change brush heads to just move the whole manifold.
Because they are on stalks of pipe they withstand the knocks, if they need adjusting, I just press/push the stalk in the direction I need. The volume is controlled by the little tap. I have another one on the pump and can balance between the two to achieve what flow I need simply by adjusting one or the other. Comes in handy to just drop the featherlight and adjust or switch on/off at the brush head.
3.They are simple hoselock micro irrigation "jets" from any good garden supplier or do a google search. I get mine from my local garden centre.
Just had athought about fan sprays but will have to go shoppingm, may or may not work but will post results at the week end.
If you want to use the spray pattern thro the brush, just carefully cut out one tuft of bristle, drill a smaller hole to get the whole nozzle cap into from the back, to bite into the brush head then drill a slightly bigger hole to accept the base of the yellow jets. You have to cut off the little wings with a strong pair of scissors and then just force the jet into the slightly enlarged hole. Doing it from the back is harder but means that the nozzle doesnt stick proud of the brush head and rub on the glass. When you cut out a bristle shank you need to fit a cylinder shield over the drill bit to stop the drill grabbing the bristles next to it. I think that removing just what you need is better than trimming out a whole row because there is more brushing power.