I don't have the experience that some of the other people do on here. I do have some thoughts, though, and I hope they help.
1) Tell her soon. The longer you keep it from her, the more it will hurt her when you do tell her.
2) When you do tell her, be completely honest with her. Yes, there may be only so much she can take at once, but what you do share with her it is important to share it with 100% honesty.
3) Allow her to feel. I can't tell you how she will react, but chances are it won't be positively. At least, not at first. She may feel angry, sad, betrayed, or any other combination of a hundred different emotions. You have to let her feel that. As much as you are going through, she will go through just as much.
4) Allow her to question. I had a million questions when my SO told me about his needs, and he isn't even planning on transitioning. I can only imagine the questions I would have had if he were. Be patient, and answer what you can answer honestly.
5) Allow her to participate. It is your body, and ultimately you decision, but if you love your wife then you must understand that every decision you make will imapct her. If you want to research, then approach her and tell her what it is you want to research and ask her to participate with you. She may not want to, and that's ok. The important thing is that you gave her the option.
All of these are based on the premise that she will eventually become supportive of your needs. Best wishes and I hope things work out for you both.