booster after Covid infection

[coachmylife]

I've had Covid recently, but am also eligible now for my booster. Does anyone know:
a) what the basis for the 'wait 28 days after your test' advice is?
b) if there's any evidence about when after Covid is a good time to have the booster. Wait for a bit, given I'll presumably have a post-infection immune response? Or rush to book?

I had covid a few weeks ago. I decided to wait until 2 months after the positive test on the basis that immunity can start to wane after about 3 months.

Sorry, don't have any links to evidence. Someone I know who works in this area, who I respect said that's what she would do if she were in my position.