LOL...
Ahh yes, the old floor tile problem.
This is my arch nemisis... Just be glad they aren't 1 inchers...
You're right to want to go hourly....but consider these facts...
why are you regrouting in the first place? Dirty?Cracked grout?
Also, if there's a shower pan failure and the water isn't draining right the floor may always stay dark/wet in certain places.
I don't know about you but I generally steer away from these things pretty bad.
If you do it, let me know how it goes

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Chris_787
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