chlorox It takes unexpectedly little effort to pressure profile. In fact, so little that the problem is not putting too much force on the lever.
When you think how the lever works, it’s not surprising: it takes (say) 25 kg of force on the lever to load up the spring with the 250 kg (11 bar on a 54 mm basket). It will take 1/11 of that force, i.e. just over 2 kg to modify the pressure by 1 bar.