It is going to be very difficult drilling the holes in both the base and jet plate, especialy with a wobbly old drillpress!. Can you get/make something for your Dremil that would work. The router attatchment maybe?. I'm thinking the tolerances may be tighter than a drillpress?...
That's goodly looking jets coming out of there. Maybe make up a 'jig/template' to hold them in place once glued for the final version?...
Were the 2mm brass tubes brought from a hobby/model shop?. I thought they might be too big (I/D) but they look OK
...