I have tried the workout before many times and its best just to start out light and go from there. This workout, if done correctly with the required tempo can really kick your ass. I start off using about 35% of my 1RM and went up from there.
Oh yeah, as far as results go, you steadily lose quite a bit depending on your diet. I tried it on a low carb diet and the workouts are really taxing, so u might not be able to keep up 3 HIIT sessions.
Again, try it out for a week, see how u feel. I lost close to 20lbs last time in 4 weeks while on a strict low carb diet. Somewhere around 10 times my bodyweight in calories.