Thanks Michael !
No need to have an automatic calibration.

This script, you gave in the forum, did the job and I had tuned the fieldOfViewAngle for my monitor resolution and size.

script: /* set top view zoom factor */ moi.ui.mainWindow.viewpanel.getViewport( 'Top' ).fieldOfViewAngle = 30.0;

I will test it for all views and perhaps adapt for another usage.