Is it possible to reliably define the times (for a specific location on earth) when the tidal gravity from astronomical objects (moon, sun etc.) are at their weakest & strongest?

I have considered using sea & ocean tide times, but these factor in unwanted variables, such as ocean currents and coastal water flows, which would invalidate the results somewhat.

I am attempting to define whether any noticeable effects occur from the moon on athletic performance, but need specific times with which to test and compare (hence the strongest & weakest times are my targets).

Is there a reliable method to calculate the times of strongest and weakest gravitational pull of the moon upon objects at a specific location on earth, in effect a high and low tide? We considered using tide times, but they factor in variables such as ocean currents and coastal flows, which would adversly affect our results. Is there a formula that can give us a good answer?

Is there a formula to give the times when the lunar gravitational effects are strongest and weakest for a location on earth? We considered the tide times, but they factor in variables such as coastal flows and ocean currents, which would adversly alter the calculations

Is gravity some kind of pure energy? If yes, how does it affect the world around it in such a large way? If no, how it is "transported" around the universe?

After arguing about it for an hour or so, a friend and I are confused about what would happen if you were in the centre of the earth.

That is, you were in a spherical chasm in the exact centre of the earth, and the earth was a perfect sphere.  Ignoring the heat and lack of oxygen, what would the gravity of the earth do?  Pull you apart, crush you, or nothing?

disregarding the heat etc would gravity hold the object suspended at the centre of the earth

My son asked this question which I can't answer!  Assume that the hole goes right through, i.e. no core.

Aside from bone and muscle differences, which have already been covered.

For example, someone who grows up without being spun around at 400m/s as the world spins; would they feel as if they were spinning when they set down or entered orbit?

I don't know when it was created, but supposedly it was a long time ago, like billions of years ago. You'd think by now, with it being only 250,000 miles away, that the earth's gravity would have pulled it in. What's keeping it back? Is it not a moon, like the Death Star? "that's no moon"? Supposedly the sun keeps pulling it away too, in the opposite direction, but I don't really get it.