Hi guys

Looking to try and make a basic FM module with operators characteristic of the FM8 VST. I have been trying to work out what the scaling on the modulation index is. On the FM8 GUI, the output parameter it is given as 0 to 100.. I found this post about it and have tried to follow the instructions but am getting no good results. https://www.native-instruments.com/forum/threads/modulation-index.6534/

Am i missing something? With a test between waves getting modulated with the maximum index, and a ratio of 2, they do not sound the same. Although their spectrums are similar, they are not the same. What does the modulation index get multiplied by to scale it correctly?