Best practice to convert and reproject Sentinel-3 radiances to reflectance

Optical Toolbox
15

Do you mean:
C:\Users\<User_Home>\AppData\Roaming\SNAP\modules\org-esa-s3tbx-s3tbx-rad2refl.jar
to <INSTALL_DIR>\s3tbx\modules where the existing copy is?

If I put it in s3tbx\modules now on the line:
obj.readPixels(0, 0, w, h, pixel_values)

get the error:
RuntimeError: java.lang.RuntimeException: Cannot construct DataBuffer.

EDIT: Correction this now seems to work!