3/4" endmill came from Enco this morning (Interstate brand is Red
Chinese, no surprise), ran down into the basement and put two .200 deep
pockets into the .250 thick 6061 bracket. A bit of curiosity when I
attached the scale, but it pulls quite tightly onto the head.

Endstate: this looks decidedly clunky, BUT I didn't have to drill and
tap the quill OR the head. Only "problem" is the damnable data port is
not the same dimensions as the data cable plug.... Yet to figure out a
mounting solution for the DRO 3 axis display. Right now it's attached to
the mill head via the magnetic backing.