"In other words, how can I keep a 120 scale enlargement to a part while making it appear to be 100 percent on the scale dial?"

You can't.

Let's take Jessi 1 as an example. Her forearms are WAY too short for an "average" human being.
If you scale them up along the x-axis to correct that, her hands will of course move along the x-axis, too.
If you just re-save her, the scaling of the forearms will not be re-set to 100%, but stay at the value you dialed if you load her again.
(Props behave different. If you exporte and re-import an object, it 's scale will be reset to 100%)

So to get all scale values back to 100%, you need a new object.
But if you export that scaled Jessi as an object, and use that object to create a new figure with the bones of the unscaled Jessi, all the hand joints will be off and you'll have to re-rig the hands and fingers from srcatch.

It would be actually nice if there would be a way to do this automatically because matching clothes for scaled figures can be a pain, (and I use scaling a lot because the proportions of almost any Poser figures are way off), but so far I never have heard of a script or program that could "scale" a poser rig.