Request advice about Applying for Convalescent Temp 100% after Surgery.

[wilspeak]

Hello fellow Vets, I am scheduled for surgery in February 2017, for a service-connected injury. I will have a joint corrected and bone surgery. I will also be in a cast or other therapeutic device for at least 12 weeks.  What exactly does the VA need in the way of medical records or statements in order to be approved for the temp 100% convalescent rating?  What exactly does the letter from doctor need to say? what exactly does the discharge summary need to say ? and how long does the Convalescent Temp 100% pay take to get approved ?  Thank You all in advance