This is from a previous thread. You can be the judge.
I think your numbers and variance for Verbier give a fairly accurate estimate and results are simliar to information I have seen where estimates are compared with recorded power data. I think around 400W for Contador and 440W for Wiggins sound about right. Generally it is easier to estimate wattage climbing than Time Trialing because gravity is the major force to overcome rather than wind. In time trialing the rider position is really hard to estimate and makes a big difference.
I am not convinced of an upper limit of 6 W/Kg being possible for a 20 min climb or whether weight makes a significant difference to possible power depending on body type and style and shape of the rider. Assessing the difference in weight lifters across different classes could provide relevant comparison of muscular power. Oxygen capacity, muscular and energy efficiency seem more relevant to the power output than the riders muscular power.
Bigger riders tend to have lower W/Kg than smaller riders and this makes Wiggins figure look more suspicious. I think I have posted in other threads examples of riders achieving 6.4 W/Kg for an hour while having no access to EPO
I think the variance in power data shows that Wiggins can produce higher power numbers while climbing than on the flat. This is my own experience as well and think it may be related to muscular stress of using bigger gears but dont have enough evidence to prove it
Corners and inconsistent power required in TTT must make a significant difference also.
Not sure whether these would total a 60-70 Watt difference but is possible
Another factor I didn't think of before was that he built up his form as the tour went on. Trainers and scientists cant yet explain the reasons for this but evidence suggest it happens and riders use tours for preparation as a result.