I am sorry, perhaps I did not make it clear and created some misunderstanding. As I mentioned for dispatch purposes the weather is checked against the minimums on the approach charts. The legality issue is well-defined in this case.
But as B737900er mentioned I was hoping some would share experience as to how as pilots would you interpret and relate the weather to the minimums on the charts, including uplift of additional fuel. This is the main point.
The guide given can be quite useful. We are however not advocating for not conducting the appr with the rule of thumb. It is only an assessment of weather for contingency planning.
Just to share, in the Asian part of the world where tropical thunderstorm and rain prevalent. It does seem to reduce the visibility considerably so much so that there seems to be a possible need of a reduction factor from the rule of thumb. Different regions with the different characteristics for weather.
Thanks again for sharing.