I went this way:
for (byte i = 0; i < customchr_qty; i++) {
memcpy_P (lcdPrintBufr, &ramGrfx[i], customChr_s);
lcd.createChar(i, lcdPrintBufr);
}
It's more compact and cleaner, to my eye, and no matter how I set it up memory usage was unchanged.
On the learning curve front, testing @johnwasser 's approach, it finally sunk in about the name of a character array being a pointer.
A nice side benefit is that on top of saving forty-eight bytes of RAM, flash usage dropped sixty-four bytes.
Thanks for your input!