Crossfit- how would you enter that?

Since there as so many variables in Crossfit WODs, and each individual's scaling and intensity levels, there isn't a universal answer. What I did is wear a heart rate monitor that calculated calorie burn in a number of different workouts. For me the workouts kind of averaged down into two classes: "regular" crossfit, and "running" crossfit (the highly aerobic WODs). I've been using these two burn rates (you end up with a view of calories per minute) and vary the number of minutes of each workout session since wearing a HRM during the WOD isn't much fun (especially burpees--landing on the floor on your chest with a chest monitor attached kinda hurts). I hope this helps.