In regards to the tool path view, the only reason a machine can not follow the toolpath accurately in exact stop mode is if the step resolution is so poor that it can not possibly go to the requested position. Of course the display does not take into account machine flex or backlash....... which in the real world actually running parts can make huge differences.
What speeds you can set for different angles in the CV wizard is entirely dependant on 2 things. Your axis ability to accelerate and the tolerance you have to hold your tool path to. Its simple physics. Does your machine run like a pro-mod drag car, an Indy car or a bus? No mater how it performs, CV is a trade off. Nothing happens instantaneously. No matter how much accel and rigidity a machine has it cannot go around any corner (angle) without rounding it unless it stops at the end of one line and starts back in the direction of the next. End of story.
Now, what the CV wizard does is limit the feed rate to whatever you set it to for any given angle. It does not limit the feed rate in straight lines, only in corners (direction changes). So say your machine can take a 90 degree corner and only rounds it by about .010. If the tolerance you have to hold in that corner is .005 the .010 is not acceptable. So how fast your machine can take that 90 degree corner and still hold the .005 tolerance is the question. Unfortunately, your the only one that can answer that question. So, you have to do some testing to find out. When you do your testing I would do so in the worst case scenario (biggest tool, deepest cut in hardest material etc.). All of these considerations are trade offs as well. Maybe you use a 1.000 2 flute end mill to surface your aluminum table but most of your cutting will be with a .250 v cutter in styrofoam. So do you optimize the CV wizard to surface the table, do some v-carving in foam or somewhere in between? Lots of things to think about. This is why predefined (before the build begins) specifications are not optional if you hope to end up with a machine that will meet the end users demands.