Anyone tiled over chatahoochee riverrock?

My rear patio of about 600sq ft is chatahoochee riverrock. Half of it is in good condition as it was unexposed to elements. The other half is pitted with lots of loose pebbles.
I've explored my options and the cheapest and nicest route seems to be to lay down some thickset and do some outdoor tiles.
The slab that the existing chatahoochee is on is around 18 years old and it has remained fairly flat to the eye. No easily noticeable areas of settling aside from 1 crack down the entire piece.
My questions are
1) Has anyone done this and how were the results? 2) Prepping, can pressure wash away as many loose pebbles as I can and then put down thickset/title? Or do I need to have the chat re-sealed so there are no loose peebles?
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