Hi,
keep in mind that the given values for takeoff and landing are what experienced test pilots on new material achieved. The regular hobby spam cam driver in his worn out material will never come close to these.
I would like to add that there are more places in Europe than spain where one can see an impact on performance whilst taking off or landing. There are a lot of airfields with 1000-1500 feet ASL, add low pressure and 30 deg C in summer... you get the trick?
I would always calculate the correct distances and performance. And I would always add a safety margin of x percent for worn out engines and airframes and x percent for me not being a test pilot.
Kind regards,
Peter