Lou has a Jung pump in his adt. We were looking at the insides when I was visiting him & Greg a few yrs ago, if memory serves me correctly, gears were about 1/2inch dia and maybe 1/4inch width, with approx 5 or 6mm shaft. I don't know what the inlet/outlet hole sizes were.
Jung rates their pump flow ccm/revolution. I think my 850 has a .3ccm/rev with a large brushless motor (guessing 10 000rpm) using a 1:2.5 belt drive reduction = 1200ccm or 1.2L/ min flow. With 4mm flow lines, except it's 6mm lines from the valve to the Y connections of the boom and from the Y to the paired boom cyls is 4mm.