I need a detailed script to create a rectangle and adjust its size.

Hello, I need a script that creates a rectangle with the total area size of the objects I select and makes size adjustments.

It needs to include these;

1- It should create a rectangle with the total size of the objects I selected.

2- Fill none. The stroke must be a spot color named "MONTAJ" in red.

3- Measurement should be added. Width:+120mm Height:+280mm

4-Measure fractions with numerators added must be converted to whole numbers. (valid for width and height separately).
Example:
Between 1750-1799mm, 1800 should do it.
Between 1701-1749mm, 1700 should do it.
(There should be a minimum difference of +60mm between the old measurement and the new measurement. If it is less than +60mm, it should be adjusted to the upper integer.

5- If the total number width or height is less than 400mm, it should be fixed to 400mm.

Finally, the measurement should be written as text. (This is not very important.)

I know it's hard but I need it. Thank you.