I use RhinoCam, which is basically the same as visual mill. Take a look at the online tutorials. Also, I use the onsrud 37 series engraving tools to do v-carving for for inside and outside, they have a flat bottom as tight as .005. They work pretty well. I also cheat a bit and use the 37-15 for v-carve roughing (to be able to get into the tight areas) by calling it a straight bit for rhinocam. (The program compensates for the taper so it doesn't matter and allows me to use a small flat bottom surface area to get inside letters, etc.) The other thing to think about is how visual mill expects the taper to be input for the tool. If the bit has a 60 degree taper, Visual Mill only wants half that because it only cares about the angle from the center of the bit. If you get this wrong it will make a mess of your lettering.