My husband and I did the ERA helicopter glacier/dogsled tour in Juneau a couple of months ago, you will love it! The helicopter holds 5, including the pilot. It's like putting 5 people in a smallish car. The ride was not very bumpy and the view is incredible! I'm sure you will be a little nervous, but afterwards you'll want to to it again! They do weigh you because in helicopters they have to distribute the weight evenly. They will place the passengers so the weight balances the helicopter better.
It is the most amazing tour and the dogsled camp is a wonderful experience. You will actually ride on the dogsled for about an hour across the glacier. Here is a picture of our dogsled ride. I was sitting in the very front of the sled when I took this picture.
What helicopter company are you going with? Here is a picture of the helicopters coming to take us back to Juneau. They are very professional and will take good care of you.
Have a wonderful time and report back to us.