I did mine more like the second link
I used a 0.029 endmill to drill the orifice in the tip, and mixing block. Used an 1/8 inch brass tube for the extension. Drilled an 1/8" hole through the mixer block, drilled 21/64" for the fitting threads. Used JB weld to glue the brass tube in. For the coolant feed I drilled a pilot hole 1/8" down to intersect the air hole. Drilled 21/64' just deep enough to tap the threads. After the brass tube was glued in place I used the 0.029 inch end mill to drill down through the coolant feed hole, and through the brass tube to make the orifice.
For the coolant container outlet I drilled the brass fitting through 1/4" to allow the tubing to pass through into the bottom of the container. Used a plastic compression ring, inside the compression fitting. Also pushed a brass tube inside the tubing to support it for the compression fitting. Hope that explains it.
Gkamysz, I really liked your web page description of the spindle. Some day I want to make a small spindle for cutting balsa, and engraving. I had purchased one, but was talked into including it in the sale of my small mill.