I have two friends that are over 6'3" who are transitioning at the moment. They're so tall, that they have to buy their clothes in specialty stores on-line that cater to tall women because of the extra limb lengths needed. Foot size?: 13+. Both of them recently (within the last 6 months) went full-time at work. They're both happier and more relaxed than they've been in a long time, now that they can be themselves...and work is going well for both of them. So far one passes ok (and will look even better after healing from their FFS next month), the other is taking things slow, and while she could probably use some help in the passing department....what matters is that they're both happy. And they're both working toward living a life that reflects who they are.
.
Personally, I'm just shy of 6', but very burly with broad shoulders, and the extra weight I'm carrying doesn't help either. The whole time I was growing up, I'd always get comments about how big my shoulders were (bleh). I guess what I've found is that despite this, the body isn't that hard to deal with. There are a lot of tricks you can employ to alter your body shape presentation. By wearing certain cuts and styles you can accentuate/downplay proportions and features to give the impression that you want. Yes...even for someone with football shoulders like me. It does cut down on your options a little, but not as much as you may think. Personally, I thought I'd never wear a cami in public simply because my shoulders were too big...but it worked just fine last Summer...and I'm looking forward to doing it again this year.

Little accents (jewelry, makeup, etc) also make a big difference. A lot of passing is about subtlety, and sending the proper gender cues. And as said above somewhere, confidence, presence, and attitude are a large part of that.
.
Passing perfectly isn't the end-all-be-all of things. I know I don't pass perfectly. I'm rather large for a woman, my hair has a couple of thin spots that are a bit noticeable, and my facial profile is horribly masculine. And despite all of that, I generally pass most of the time due to everything else mentioned above. Just remember that there is a lot of variation among women. I know I'll definitely never be a model. Square-faced Germanic Hausfrau is about the best I will ever do, but if it means that I can be me, it's more than enough.

.
So do what you need to do to be happy, and to live a life where you can be open and honest about who you are. Whether you're big and burly like me, or tall like my friends, or even if like me you don't pass perfectly...you shouldn't let it get you down. A meaningful happy life is possible for you.