Gaza,
These jets I believe can be bought from cleantech, also Peter at Broxburn cleaning will have them.
The internal bristles are the only ones removed of course, and it doesn't affect the cleaning one iota.
I've not fitted jets myself, though care has to be taken I would imagine on the angle you fit them, get that wrong and you will ruin a brush head!
I don't hold the brush of the glass to rinse, I personally find it better to leave it on the glass, the washing and rinsing is a continual process anyway.
On repeat cleans I am washing and overlapping very methodically, so that I know I am rinsing as I am washing.
On first time cleans you always have to take more care, from what I have seen, and I am not necessarily correct in I disagreeumption, the needle type jets appear to be better for the holding of the glass to rinise, by virtue of the fact that at any one point there is always far more water hitting the glass than with the fan jet.
The fan jet may well have just as much water, but it is spread over anthing up to a couple of feet in width, depending how far off the glass you hold the brush, ergo I think it possible that the 'rinse effect' is not as good as with the needle jets.
so you are better leaving the bristles in contact with the glass so that the bristles aid you with rinsing. And I have yet to have a problem with contamination.
I want to try the Ionics brush, their domestic one, but I'll have to make a fitting for it to be able to fit to the Unger poles I use.
I don't like the idea of the spray coming over the top of the brush, though proponents of this mode would argue that you are continually rinsing behind the brush, i.e, contaminants are being continually flushed as you work, so a contaminated brush wouldn't be a problem..they might have a point?
As I have mentioned elsewhere, Peter Fogwill has (or is still doing so) developed an automatic brush head, one tap on the window frame turns on the flow, a second cuts it off, sounds very good to me, I'll be really interested to see how it works in practice
Time to go shower!
Ian