User Hubert K notes of the constrained simultaneous fitting tutorial:
FYI: this tutorial has a problem. If you follow instructions of adding ALL then deleting unneeded, it checks the fit boxes of the SLDs. You need to go in and uncheck them before fitting. A second, typographic error is that instructions say to set radius constraints M2=M1 and M3=M1, but the example panel shows M1=M3 and M2=M3. the two different methods give somewhat different end values