If you use Algarde or can get hold of some, jetting is so easy.
Get a thick drinking straw and cut it into 1cm lengths.
2] get some darning needles.
3] get a piece of smooth polystyrene packaging.
4] get a tube of Araldite rapid.
Mix the Araldite and fill each piece of drinking straw, wax the darning needles lightly and after placing the pieces of straw on the polystyrene push the needles through, the taper of the needle lets you choose the jet diameter, and the needle goes into the polystyrene or a piece of plastic blister pack if you like.
When the Araldite goes off pull out the needles.
If you now take off the plastic straw you are left with a plastic jet that will push into the end of the Algarde hose.
Drill a 5 mm hole through the brush and push a length of Algarde through the hole [not easy as the Algarde is 6mm diameter] this is easier if you cut the Algarde so that you have a pointed corner.
When you have the Algarde through the hole you can cut it off square.
Now insert your plastic jet into the end of the Algarde, make sure you have a long enough length to allow you to fit your Y piece.
I leave the jetted piece so that it's flush with the top of the bristles, the jets are actually on the glass, no danger of scratching as I push the jet far enough into the Algarde which is made of silicon.
These jets work a treat as they are not having to fight against the bristles to get to the glass. dai