Shimode-san's measurement had 1000 times gain. It was written at title of measured graph, or see log in the zip file.

Measured point was at the direct output for coil with no coil or no resistance), not at the monitor point.

Detail for measurements is shown here;

http://gwclio.icrr.u-tokyo.ac.jp/lcgtsubgroup/electronics/2018/05/coil-driver2.html

See 3rd method on atatched Exel file on above page.

Even measured data for 3 dewhitening stage was not limited by detector noise. You can use all the data directly for calculation if you devide by 1000.