Leo,
That have been programed by repeated meeting attendance, and have it drummed into their heads "obey the F&DS" and "they are the channel for understanding the truth" those mantras are hard to penetrate. For the average JW to doubt or question the GB is a deadly sin that causes their minds to shut out any information that is critical of the GB, they are under a painful fear of displeasing Jehovah.
Any information you wish to give them has to be done very gradually without pushing any alarm buttons that will cause the minds reasoning power to shut down, questions have to be designed to subtlety broach the subject and gradually lead them to more reasonable assessment of the GB. Proceed too fast and the repeated programming kicks in and they will shut you out and run from any further discussion just as they have been trained to do by repeated indoctrination they received from the WT.
The ones that listen are those that have been thinking about it for a while and to some extent have been doubting already, unless they are ready you won't get too far.
The main thing is don't try and clobber them with information proceed gradually and try not to set off any triggers of alarm.