[sfem]

No-one can predict whether NBE will quiet your inner desires or strengthen them over time. If part of your turmoil is religious, will finding soft, round, feminine breasts on your own chest cause you unresolvable moral anguish? My experience of people truly committed to their religion is that they aren't usually open to things not blessed by the organization that codifies their religion. Will that be a major source of unhappiness for you even if NBE does help with your GID? Your post suggests you aren't interested in this for sexual gratification, either the cross-dressing or the porn aspects, which I think is a key piece of what gets quieted down by NBE. I hear that you have suppressed your own beautiful inner self for the sake of those you have loved and still love. That is both admirable and very sad. I feel for you. Many of us do I think. I don't know you but I would be willing to bet that NBE can help your body to blossom into a wonderful form to match your inner qualities. I also suspect your feelings for your extended family will cause you to always be unhappy at causing them confusion about you once they start noticing your changes, even if they are mostly mental. It does sound like losing some of your church-based straightjacket wouldn't be a problem for you and that is good. But given your long involvement with it, you may be surprised to find how deep that programming has been installed in you.
At your age most men lose some of their macho ego and their bodies become less masculine. They get away with clothing and behaviour choices less socially tolerated among younger people. Dropping some religious dogma from your life is always good for your soul. Your younger family members such as grandchildren will be far less disturbed by these changes than you might think given changes to early education and exposure these days (I'm assuming you aren't in Texas or Arizona or one of those places where children are taught in the public schools that the Sumerians didn't exist because the world hadn't been created yet). Unless they are already being indoctrinated into a religion in which case they are already having their ability to decide things for themselves stripped away.
In the end you have about the same set of conflicts many of us here have. As you read past posts and going forward, you will find there are as many consequences as there are people here multiplied by the number of choices each has. I wish you the best of luck whichever way you go and I hope your other family members find the strength in themselves to accept you for who you are, not for who you look like.
Most people who talk about brain-rewiring here talk about it with respect to PM, not the other herbs. They also talk about it moving them towards a more feminine brain, or in a few cases soothing their distress perceived to come from feeling feminine but not looking it. So it's very hard to say if NBE will quiet your inner desires or strengthen them over time. I look forward to hearing your story unfold.