The .08 was referring to the jet size. as far as backing out the "screw" it can go as far as 1/16" or 2mm past the end of the valve collar edge. Best way I can explain it.
Yeah it is a bit of work to make a change for sure. My valve return was also set to flush with the end of the valve body. I think the jet in the balanced valve was .030" diameter.
My valve return was set about 1/8" in from the valve body end, my friend Steve backed it out to about 1/16" past the valve body end to help with power increase.