Originally Posted by Campag4life

What else do you need other than the data?
You have three helmets. One has a lot of holes and great for ventilation. Second has same profile but it more closed up. Third is pointy and closed up.
Which do you think will be faster? Go to closed course on still day. Testing time. Perform 3 laps of 2 mile oval negating wind and elevation change. Test each helmet at 250 watts against the clock with a power meter. Identify the fastest helmet. Greater reliability? Repeat.

Which helmet are you going to bring to race day if the race isn't long and 100 degrees?

No R Chung method. Number of grams saved of drag even if can even be measured reliability isn't relevant. You want the fastest helmet.