We’ll do tails first since that is the board which is held vertically and a bit easier to visualize.
The next consideration is how many pins / tails there will be — as noted, we are constrained by the endmill geometry in a way that we are not when cutting by hand, so the tails have to be greater than 0.5" at their largest dimension, and must be at least 0.25" at the base. With a 5" tall box, we will simplify this and have 5 tails/pins, with a half pin at the top and bottom.
One way to do this visually is to draw up a side view of the tails, evenly arrange the tips and then use the drawn up tool to line things up:
With that done, we can begin to draw in boxes to represent what will be cut and what will be left behind.
One has to consider that one will be working with a 1/4" endmill which will be cutting from the center out in Carbide Create, but the actual path ultimately will be the dovetail bit which will cut a 1/2" diameter at the bottom. We will need to leave clearance at blind side to ensure the dovetail bit doesn’t blow out, and overcut on the other to ensure that we will have a clean, square cut of the sides of the tail — drawing in some circles will help to visualize this: