Hey PY - my best suggestion is know yourself.
I was diagnosed with lupus in 1999 after my son's birth - although I had been struggling with symptoms for years. I had weight loss sugery Nov 2004 - a radical version of RNY I knew that it would be difficult to revise my eating/lifestyle habits of 45 yrs, so I chose a surgery which virtually had a history of no weight regain but could have chronic malabsorption issues.
I have friends who have had RNY and virtually gained all their weight back!!!! I couldn't face that possibility. Choose one that you can live with for the rest of your life. My advice in terms of lupus - rest and exercise, exercise and rest. Choose a surgeon who listens, and who has a good track record --- talk to some of his patients who have had the surgery and ask about his after-care. Do his patients participate in a support group? (My surgeon made it mandatory)
All the best to you
B