The structure investigated here has a future application as a plasmonic sensor. Different Minimizer methods, for finding the best, data fit will be discussed and compared, such as the Levenberg- Marquardt, Gauss-Newton, and Differential evolution methods. The paper will aim to determine the best method for the sensor application. To compare methods, several different simulations were held. Important parameters used for the comparison are the accuracy of methods, number of evaluations, time, local minima handling, etc. The dependency between time and accuracy will be demonstrated.