[cypher]

I would remove the bedding that’s in there now, put the new in, as deep as you can then spread some of the old on top just to keep his scent in there, that should reduce the stress & if you can do that without disturbing his nest too much he should be fine.
They do sometimes pee & scent mark everywhere to begin with but once they’ve settled on one spot you & with deep bedding you shouldn’t have to clean much after that.