A method for controlling and optimizing the transverse uniformity of a coating thickness on at least one side of a running metal strip in an industrial galvanization installation, said coating being deposited by hot dip coating in a pot containing a liquid metal bath, said hot dip coating comprising at least the steps of: - heating the metal strip substrate to a temperature higher than the pot temperature; - passing the metal strip through the bath by wrapping it around at least a first deflector roll or sink roll followed by at least one second deflector roll, said second deflector roll being intended to improve the flatness of the strip; - wiping excess coating thickness carried away by the running strip on one or both sides of the strip by wiping nozzles (5, 6) blowing a gas on the coated strip at the exit of the liquid metal bath; - if this additional equipment is available in the installation, passing the metal strip through a contactless actuator system located after the nozzles (5, 6), said contactless actuator system being able to exert a force on the running strip for modifying the position and/or shape of the strip; said method comprising at least the steps of: - measuring an actual distance profile between the nozzles (5, 6) and the strip along the direction transverse in respect of the running strip direction, and in the vicinity of the nozzles (5, 6), so as to obtain an actual nozzle to strip distance profile curve (14, 17); - using a computer, calculating a first correction on the nozzle to strip distance profile curve (14, 17) based on the calculation of the average slope, that is 1 st order linear regression straight line of the nozzle to strip distance profile curve (14, 17), aimed at applying said first correction to take into account the skewness of the nozzles and to set the nozzles parallel to the metal strip; and - calculating a second correction on the first corrected nozzle to strip distance profile curve by substracting from said curve a 2 nd order linear regression quadratic line, the result being a second corrected nozzle to strip distance profile curve, aimed at applying said second correction on the second deflector roll(s) in the pot to compensate for the crossbow; - acting on the nozzles position and transverse metal strip shape by physically transposing to the industrial galvanization installation the first and second calculated corrections, as a first and second corresponding physical corrections, by modifying firstly the position of the nozzles (5, 6) and secondly the shape of the metal strip respectively, so that to obtain a coated metal strip which is physically corrected in position and shape; - if said additional equipment is available, further acting on the coated metal strip which is physically corrected in position and shape, using the contactless actuator system, as a third physical correction, so that to obtain a coated metal strip having optimized flatness. - heating the metal strip substrate to a temperature higher than the pot temperature; - passing the metal strip through the bath by wrapping it around at least a first deflector roll or sink roll followed by at least one second deflector roll, said second deflector roll being intended to improve the flatness of the strip; - wiping excess coating thickness carried away by the running strip on one or both sides of the strip by wiping nozzles (5, 6) blowing a gas on the coated strip at the exit of the liquid metal bath; - if this additional equipment is available in the installation, passing the metal strip through a contactless actuator system located after the nozzles (5, 6), said contactless actuator system being able to exert a force on the running strip for modifying the position and/or shape of the strip; - measuring an actual distance profile between the nozzles (5, 6) and the strip along the direction transverse in respect of the running strip direction, and in the vicinity of the nozzles (5, 6), so as to obtain an actual nozzle to strip distance profile curve (14, 17); - using a computer, calculating a first correction on the nozzle to strip distance profile curve (14, 17) based on the calculation of the average slope, that is 1 st order linear regression straight line of the nozzle to strip distance profile curve (14, 17), aimed at applying said first correction to take into account the skewness of the nozzles and to set the nozzles parallel to the metal strip; and - calculating a second correction on the first corrected nozzle to strip distance profile curve by substracting from said curve a 2 nd order linear regression quadratic line, the result being a second corrected nozzle to strip distance profile curve, aimed at applying said second correction on the second deflector roll(s) in the pot to compensate for the crossbow; - acting on the nozzles position and transverse metal strip shape by physically transposing to the industrial galvanization installation the first and second calculated corrections, as a first and second corresponding physical corrections, by modifying firstly the position of the nozzles (5, 6) and secondly the shape of the metal strip respectively, so that to obtain a coated metal strip which is physically corrected in position and shape; - if said additional equipment is available, further acting on the coated metal strip which is physically corrected in position and shape, using the contactless actuator system, as a third physical correction, so that to obtain a coated metal strip having optimized flatness.