Oh Marilyn, I sure can't help to advise anyone how many acorns to use for the NARR. I have used more than 25 acorns and not won anything.
I tried using a single acorn and...didn't win anything.
There was one time that I did win; I remember, must have been about a year ago...I gave up the 'real' prize and opted for the acorn prize.
Good luck to everyone in the NARR.