Set anchor for mouse transform tools

Is there a way to set the origin for scaling/rotation for the mouse transform tools? I know there is a script for doing rotation around an anchor, but is there a way to set the transform origin at a specific point (with the option of setting it at bounding box co-ordinates) for use with the mouse to get visual real-time feedback, instead of setting numbers and doing calculations?

Just click once when the tool is activated, exactly like the scale/rotation tools in AI. For realtime visual feedback without calculating anything, you do not need the mouse. With a node selection and an origin set, simply click into any number in the grey info box, and press up/down arrows. Add Shift for increments of 10. The drawing will update immediately.
But I can't set at a specific point, lets say (0,0) without zooming in? Id get maybe (-3,-2) if I'm not careful? Also I'd just like to scale visually, and being able to set the scaling anchor numerically at least would make this easier.

Edit: I’ll try just clicking and seeing if I need more accuracy.

It's cumbersome to scale numerically especially in this circumstance:

I’ve drawn a shape and need to scale it, I’m not quite sure yet how much I want the shape to be scaled - It could be anywhere between a 5% to 15% - In a situation with a bounding-box scaling tool I usually do some visual experimenting. In Glyphs app I do the follow:

I have 3% in the transform box. I click +, or - and repeat until I get the right size. Sometimes the scaling factor is too much so I have to retype the value to a smaller step such as 1%.

It get’s more cumbersome for isomorphic scaling, if I was scaling only horizontally but now wanted to scale vertically I have to clear the value in horizontal box and then retype something into the vertical box (probably the same factor), there should at least be a swap values button otherwise?

I was not talking about the Scale tool. I meant the grey info box (View > Show Info). Select something and you will see width and height (indicated with double arrows.

Now, click in the number, and press uparrow/downarrow a couple of times. Add the Shift key for increments of 10. The lock allows you to scale x/y proportionally.

This way, you directly set the bounds of the selection. And you do not need to know in advance how much you need to scale. You can just try around until it looks right.

Still, I'd like to be able to set the anchor by entering numbers, then rotate with the mouse (WYSIWYG), not the plugin 'Rotate around anchor' plugin where I press a button repeatedly to rotate? Right now it's too much to zoom in a lot and set the rotate-origin manually..

I’ll write a script for that.

EDIT: In my Scripts repository, in subfolder Paths, you will find a script called Set Transform Origin. You can download all scripts, and find all necessary installation instructions on https://github.com/mekkablue/Glyphs-Scripts