I also live near LCY - because of this, I will always fly from there wherever possible. I am 6ft1, relatively broad, and am a bit uncomfortable on these flights, but compared with the hassle of going to one of the other airports???
Landing at Gatwick means it takes me about 2 hours from landing to get home (if I'm lucky). I'm home 20 minutes after landing at LCY. And if you factor in the extra time you need to be at Gatwick before your flight leaves you're easily saving yourself 4 hours flying from City.
I would suggest trying it this once - maybe the flight won't be full and you can get an extra seat between you. If it is really horrible, the flight is only 2hrs40 - stick a movie on your iPod and have a few drinks.