I am so excited for you. Becker is among the best in the business.
However, i do want to ask, will you be getting ITB release? Unanimously from most diaries i have found, and also from the works of fellow renowned surgeons i.e. Paley and Goitikas, , and there are also another medical journal i found on the problems of stretching the ITB , if you're going to lengthen beyond 5cm, you really should be considering a proper ITB release prior to surgery.
Read RB's diary, especially him before and just after full ITB release.
There's no doubt you will work hard, and stretch, but the ITB is one of those areas which is very resistant to stretching according to medical journals, and imo it is one of the reasons why a lot of people quit / don't make it to their goals / suffer from wide legs and element of duck ass (yes, indirctly as it is all linked).
I will be getting my surgery in a few months too, deposit paid and all, Becker is one of the best, but i don't think a soft ITB for anyone lengthening beyond a few cm is enough.