This is a walkthru on modifying controlled morphs for Genesis figure in DAZ Studio 4.5
For this guide, we are going to use the "Mouth Open" because it is just a slider that chained to two other morphs

In most cases you can change the max value right in the parameter flyout.   In this case though, the box shows that the slider controls at least one other morph and also gives the path to that file.   We will add our new max value while we are here and then move on to next morph,  CTRLMouthOpen.
For the next step, we are going to use our favorite text editor, because I have not found a way to access the files from inside DS.
If you open the file and see something like the first picture or just other scrambled stuff, don't worry.   It just means you have tried to open a compressed file.    Starting with DS 4.5, some of the dsf's were compressed.   I just open them with WinRAR and extract the file inside.   The file inside will not have an extension which is good for our purposes, since we don't want to overwrite the original.   After extracting, change the extension on the original (I use ".dsf-orig") so it won't get loaded and add extension ".dsf" to extracted file.    Now we can use text editor to change our new max value (circled) and we see the pointer to the other file we need to modify.   It's done substantially the same way, so I'm going to skip the graphics.
After we have set both max values to 6, we will try the new settings in DS.   In this particular case, the mesh starts to break after about 4.5, the 6 value was only a guess.    If we want to make the max value to 4.5, it only has to be done in the control morph. It doesn't hurt anything to leave the high max.
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