Before your question got "off track", you asked about almond oil. I stopped using OO (Olive-Oil) after my fifth flush because in spite of all the tricks (straw, mouth wash etc, etc)my body did not want it any more. I have used almond oil very successfully maybe 5 or 6 times since then , and can highly recommend it. I have had equally positive experiences with walnut oil, but find the almond oil a bit lighter in taste. For me, both do the main job well( getting the stones out), without the gag reflex.
Wishing you success!