Hi,
Apple cider vinegar will definitely break up the stones,take one table sp in water about four times a day for at least a week though before the LF.Also ,eat lots of apples.These are all I have ever taken before my LFs(five so far)and I have never experienced any pain or stuck stones.Also,make sure you take all the Es and follow the Clark protocol.
Good luck and God bless.Please let us know how you come through.
Surley.