Hi all - just wanted to update everyone on the outcome. We spoke to the CM in the CL lounge the evening before our flight. We explained that if our flight was 10 minutes later we would have been on a different DME bus and would really like to try to get on it. He said he would call and ask but they would likely say "no". He called and they said that as long as we understand that we are responsible if we miss our flight - they would move us from the 7:10 to the 7:40 bus. We agreed and said we were perfectly comfortable with that.
We checked our bags in with plenty of time in the lobby. We had a half hour to have breakfast in the lounge which we really enjoyed. And, we were at the airport and through security with plenty of time. We really appreciated their willingness to work with us on it. I know they're not always able to do that. Thanks for the feedback!