Our ob wasn't too concerned about the twins growth. Apparently up to 28 weeks the twins will grow at the same rate as a singleton baby but it's after 28 weeks that they stat to do more frequent measurement ultrasounds to ensure the nutrients are being shared and one doesn't grow more than the other. I feel calm about it all now but I might start to worry more as we get closer to 28 weeks...

No belly pics but I'm feeling huge though I'm sure there's plenty of growing left to do! I'm about the same size I was with DD at 7-8 months pregnant. Saw some belly photos today of a friend's sister who's recently had twins. She was scary big. I don't know if things return to normal once you stretch that big! It freaked me out a bit.
We had two embryos put back and both took also. Towards the end I had a number of those growth scans as our little boy looked a lot smaller than his sister. He kept a steady pace of growth and by the end he was almost the same size as her. He is still the smaller baby now though

About the belly size... well you probably will get 'scary' huge but you are carrying two babies I was pretty massive too. There is one photo of me about a week before the birth and a lot of friends have commented on facebook about how fake it looks because it was soooo big lol. As far as things going back to normal well it takes some time. My skin was so stretched at the start that I could grab it and pull it out (gross) but now it has really tightened up. Sure it is not what it used to be but when I think I carried over 12pounds of baby I think it has come back pretty good.

Hope you are both traveling well.