I would plan on shadowing them for no more than approximately 3-4 days.
Even still, it sounds like the transition will be a tough one either way.
His first few days with his brand-new nanny will be difficult, but remain consistent & eventually everything will come together.
I should know.
I once nannied a little boy of the same age who had never left his mother's side as she was a full-time SAHM.
Once she returned to work, I was to care for him.
The first few days were grueling. He would literally cry + cry the first few days. The only time he wasn't crying was when he cried himself to sleep.
Within a week things had settled down. Hopefully his new nanny is patient since one must be a trooper and committed to him.
Since your son already has experienced school, his transition should be less painful than my experience.
Hope things go smoothly!
