About scaling
It is possible to scale the whole image. This is considered as an equal scale of the 4 corner points in 2 x 2 mode.
It is possible to scale the whole image. This is considered as an equal scale of the 4 corner points in 2 x 2 mode.
Select full image as Warp area (1).

Click on a node and move while dragging it to the desired position
The image will be scaled accordingly.
click in the pane on the arrow keys until the desired position of the selected point is reached (3).
To fine tune this adjustment, reduce the step.
enter in the pane the coordinates of the desired position (4).