for any LHHW based models, how should I choose a model to fit the experimental data and to estimate the kinetic parameters in the model without so much playing with the initial guess values of the parameters. In polymath 6.1, I am getting no. of local maximum with different set of initial guesses but these lack in 95% confidence level although meets R^2 value to 0.97-0.98. Which software can help to perform nonlinear regression without depending so much on initial guess of parameters and gives me global maximum values?