Hi Lewis,
Joes Volvo windscreen twin jets sound great, no I have been too busy setting my car on fire trying to make a hot system
(joke) I like the idea of fine adjustment of them with a pin though.
Jikwan, the sprays are yellow head irrigation and spray 360 degrees, I used to use them through the head, then used green or blue pencils. Now I make my own out of "Goof" plugs by drilling small holes between 1/32 to 2mm depending on how many I use (currently 4. They are a hole repair solution for the larger Hozelock irrigation pipes approx £4 for 10,put micro irrigation into google. Yes 6 will produce lots of water.