Ain't a real old timer.... but I've dug enough post holes on the farm ...
And to prove it to a friend ... I've dug a hole and put the dirt in a bucket/tub as not to lose any..... but I did the digs at almost Full and almost New....
Near Full ... you will have more dirt than you can put back in the hole .... pack... stomp...water....
Near New... you will have to hunt more dirt to fill up the hole....
I believe you will come up short on dirt on a Waxing Quarter Moon.
Do the "dig" for your self ...... just to see...
I'll add that after packing a hole on the full moon .... if you come back in two weeks the hole will be sunk in...