If you are really serious then you have to do something that will not be seen as "persacution" by them. As in, see how Satan has a hold on her. See what happens when you disobey the org and marry a worldly person. You were always a quiet one. Don't we really want people to see the org and that particular unloving "cesspool" as it really is. When under "attack" from you they will just circle the wagons so to speak. The ostriches will continue to keep their heads buried. But, if you could do something to help them open their eyes. That would be a miracle.
As letters are not to be opened but given directly to the priests (elders) then maybe postcards. On the front where a picture usually is you could print info that you found on the "official" WTS website and then refute it. Or put info about silent lambs. Someone even offered you a silent lambs bumpersticker. That might find its way on a KH door just before the end of a meeting. (although use clear tape, nothing to deface their property) OR put the bumpersticker on a car that might run out of gas and need to be parked in the KH lot or in a good spot to be seen as they drive in the lot. Just put a note under the windshield that you had car problems and a tow truck would be there soon. Then remove the car after the meeting starts. If it's on a public road what can they do? Letters are to be turned in. But, postcards can be read before turning in. And if they aren't reading them their postal carrier will be! Don't put your return address on the postcards but sign your name (married and maiden) so there will be no question that it is you.
Good luck.