This tool is already implemented in Studio via a mod that comes with the STN RePacks. It's called HS2PE and (if you're up to date) you can find the button to open it here:
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This allows you quick control of the FK/IK nodes - very handy for mirroring limbs and hands, for example.
Next, click on the Advanced Mode button:
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The Advanced Mode is a controller for the model's bones, physical colliders, you can alter the way the hair and bewbs react to gravity here, also. For the kind of face control you're after, click Blend Shapes:
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Be advised, from here, the Eyelashes and Eyelids can work independently. But each sub-window for every blendable face part has a Reset button - the reset buttons are your friend here.
The face parts are broken up into sections, but the naming convention for the individual parts is pretty confusing and doesn't really appear to be very logical in the order they're presented. You
can rename the individual parts and save your own names for each slider - I recommend being patient and taking the time to do this, just so it makes life easier and quicker the next time you open Studio and want to get straight to work.
Learning this can't really taught in a forum post, you'll have to kinda feel your way around how the sliders work. Half the battle with using Studio is getting faster and more confident with the tools you have at hand. Tools that basically seem to fight you a lot of the time
Will happily answer any more questions you might have. I'm no modder, but making fancy shit in Studio is all I do most days, so might be able to help