There are three tools that mill out a titanium abutment; the T2, T3, and T4 Tools ($40 per tool). The T2 has a radius of 2mm, the T4 has a radius of 1.0 mm and the T3 has a 1.5 mm radius.
The screenshot from the the CORiTec ONE displayed shows the amount of use for each drill. The T2 has been the workhorse in milling out the titanium abutments with the largest green bar display. The yellow highlighted bar in position 5 means that the T4 tool in currently inside the Collette. It also has a the least amount of use in relation to the others.
You can alter the diameter of the sprue to reduce mill times, or you can reduce its size to minimize your work after the mill, with the sprue removal, but that will add a few minutes to the mill time and more wear to your drills, although both are insignificant in the long run. Obviously you can’t make the diameter of the sprue narrower than the size of the screw access hole.