You have made amazing progress, congrats!!
Although, I only lost 180 lbs, I have a friend who lost several hundred pounds. She had an abdominoplasty during mid-weightloss. She talked to several board certified plastic surgeons who were willing to do the surgery on her with the understanding that she would very likely need a revision once she reached her goal weight. She was able to get insurance to cover the mid-weightloss surgery and it gave her such a boost in self confidence. About 3 years after she reached her goal weight, she did indeed have a revision and so much more. Her outside now matches her inside and she couldn't be happier.
Good luck!