By "little overcut" do you mean 2 to 3 degrees overcut? Because that's what it needs to be. Illustrations are fine to show information, but the reality of shooting the shots provides more accurate information. The very least amount of throw that naturally occurs for a halfball shot causes tge 30° cut angle to come out right around 28°. With the cb about 7in off the side rail, aiming a halfball aim puts that 28° result at center pocket.
Does that 7 inch spot put the cue over the short rail facing of the
corner from where you are shooting
Thats where i was taught to line up
Line up the cue ball From the facing to the center of the spotted ball ....half ball aim