Regarding the fact that the sliders are small, you can simply enlarge the view laterally to add more room.
So this is how it looks on my computer at a regular size (meaning I still have a correct view on the stage.

I use it on my MacBook screen (I like it better than on my second screen which is not retina.) and since it is not possible (or I have not found how) to detach the tools from the stage, then I let it on the same screen.
As you can notice, the UI can make a better use of the width of the panel actually. Maybe something you need to check 馃檪
If you're referring to the range, clicking and dragging allows to go beyond that.
not for me unfortunately. Actually I know what is happening: I click and drag to the right to increase th value, and of course when my mouse comes to the right edge of the screen it stops. So I try to click on the slider again to move it to the right and go further, and then it goes back to a very low value (e.g. I can reach 504 at the edge of the screen and click back on the slider which then displays 47)
in this case I need to adjust by typing the value on the keyboard.
How do you imagine the way to offset in the stage directly? something like you click a buutton and adjust?
yes something like that.
In the project I am currently working on, I made a first version of the skin constrain by creating a bone for the part of the body to move, and then use it as the constrain target. Then you move this bone to the place you want and it feels like you are directly moving the constrain.
Nice but actually it has a few issues and not as straightforward as the advice yo gave me. So in the new version, as you suggested I have just created constrains (local + relative) targeting the root bone. Works like a charm, but I have to set up the constrains with the values and the sliders.
So, maybe we can have the best of the 2 versions: adding a button, and you can then see a point on the stage you can move, rotate, scale, as you do with a bone. When you are ok, you click again on the same button to exit this special setup mode.
Just an idea of course, you probably need to think more to the UX of that, and the technical side, but it will kinda help!
Sliders cannot be added one by one, you can only add the whole constraint to a skin. If you mean that you want to add several constraints at once, you can actually do it easily this way
Sorry I wrote sliders but I meant constrains.
And thank you for the tip !