Correct amount of force on piece of paper when leveling bed
Actual task in your case is to find correct nozzle height for the first layer, so the force for pulling out the paper is not important. It just has to be the same every time you make calibration. Because of the different force you apply, different paper thickness and other factors, found position can only be treated as 'relative'.

To complete the calibration you will have to make several test prints with different initial heights, starting from the lowest, adding 0.1-0.2mm (depending on the nozzle diameter) before you find the right value.

Please note that 1) initial layer height is not the only factor, affecting adhesion 2) some slicer programs may add not the same amount of height that you specify