possible to fail with ds, as a lightweight?

I have a son that needs the DS so I would like to know the cost and if there is a surgeon that  will do it in Canada, I understand most Canadian have to go out of country. He would be self pay as far as I know. 6ft but over 450lbs and age 21

I think setting a scale number right off the bat isn't a good idea.

Not everyone is the same. BMI is a very loose guideline to help you reach a healthy weight. You could ask 100 women what weight they ended up at and all of them would be different. A lot depends on build, your frame size,  and genetics. For example: I am 5'4 3/4", large frame, genetically I have always had good muscle tone, and hourglass figure and my BMI shows should be between 112-150lbs (huge range) and that ideally I should be 134-138lbs. I am sitting at 145ish and I only have 19% body fat (athlete range). My body could not possibly be smaller. I have hourglass figure making me have shapely thighs, hips, boobs, arms and a small waist plus add huge bone structure. So even though BMI and doctors say I should be a lot lower than I am, I would look sickly and underweight for my body.

So keep your mind open to the scale number. I would aim for the top of your BMI then let the DS and your body figure out the rest. Just see how you feel and how your body looks then adjust your goal weight. I believe the DS is the best tool for weight loss and if you eat how your supposed to then I bet you will be VERY happy with your results!

As for surgeons you might have to travel. dsfacts.com is a great place to find a good surgeon. Dr. Ungson in Mexico is amazing plus cheap and might give you a even better deal with you already having the sleeve.

You are right, numbers are not the important thing. Thanks!