i have used Daniel's charts for years but i have deviated from using my best VDOT for all training paces. being a mid-d guy i always struggled at my equivilent interval and threshold paces and bc of that i hated those workouts and did them less often. once i started training each system at that systems' current VDOT, i started to get in better workouts and improved greatly over the longer stuff (ie: reps are based off of mile time. intervals are based off of 2mile-5k. threshold is based off of 10k-half marathon. i call this my aerobic curve.
i have applied this to all my athletes (middle, high school, and college) i coach and i have seen awesome breakthroughs in almost every kid.
obviously, the idea is to have only a slight curve or flat line (over time) but many will have different abilities that allow them to reach a certain performance. i believe that this allows for those individual differences to be minimized over time.
if uncertain of your VDOT for an event i would just work down. Complete one workout at a pace where you feel very comfortable in your ability to achieve. if you follow Daniels workout work:rest:duration rules you will be able to figure out within a few workouts where you are at.
for example
Rep workouts pace =63 VDOT - based on 4:42 mile/ 2:04 800m
I = 60 - 17:03 5k
T = 58 - 36:24 10k