Designer tool needed

In the designer, we need more precision to adjust the visual/design relative to the top of the print area frame. We use the top of the frame as a reference for the "seam distance from the collar," and we need this to be accurate to the desired centimeter.
It could be usefull to align the design to the top of the frame (= 0 cm), and then be able to enter values in centimeters for the vertical position (e.g., 5 cm, which moves the design 5 cm down from the top of the frame), and/or use the design positioning arrows with a fixed increment of 0.5 cm per click.
For example, for a print area 50 cm tall, this would represent a 1% movement per step.
It would be very helpful for our printing work, i hope this is clear; feel free to reach out if you need any clarification.
Kind regards.