To determine how close the monitor can be to the wall when using the LC-EQ-A49W monitor mount, consider the dimensions of the mount itself. The extended arm reach is approximately 60 cm, and the height adjustment range is from about 20 to 47 cm. However, the specific distance from the wall to the back of the clamp is not detailed in the available information. Generally, the C-clamp bracket used for mounting will add some distance from the wall, but the exact measurement depends on the clamp's design and how it is installed. For the most precise measurement, it would be best to consult the product's manual or contact the manufacturer directly for detailed specifications on the clamp's dimensions and how it affects the overall distance from the wall.

Is relatively much space, would say between 18 and 1cm

By mounting the arm so that it is off-centre, you can adjust it so that the screen is aligned with the edge of the table.

As this goes up to 49". I don't think so

The height is 47cm at the maximum setting of the bracket. However, this corresponds to the height of the VESA mount. So depending on the screen size, the space available underneath varies. You can find more details on the manufacturer's website: https://www.lc-power.com/en/product/pc-monitors-cables-arms/monitor-arms/lc-eq-a49w-flexx.html