Personally, I would say 6 months to a year. Takes at least 1 year for scars to heal 100%. But I am obsessed with caution. So I waited two years. Just kidding...

No, after SRS I really needed time to settle... it took me well over 1.5 years to be able to muster courage and strength to go through FFS (emotionally). FFS truly kicked my ...
And I do agree with Mirya, surgery takes a lot out of us... not only physically, but also emotionally. So ask yourself after the 1st surgery: how big is my buffer? both physically and emotionally.
And as Inarasarah said: take as long as your body needs.
Before SRS I went on a diet, and lost 25 pounds of weight. I quit smoking and drinking. I also did cardio, so that I could take the surgery regarding cardio health and stamina. Because it's all down to stamina. It's exhausting, and it can get to you. So be your best.