My understanding of yellow BMs is lack of bile. It can also be caused by pancreatitus which occurs when enzymes start to react within the pancreas rather than first being released into the digestive tract. The enzymes help to make the whole process work. Basically if you have dark BMS then you have reasonable/good bile movement and the rest of the system is working well. Clay/whitish usually means your liver itself is stuffed commonly seen with hepatitis and other liver diseases.
I did my first flush recently and got no stones that I could distinguish then for a number of days I had yellow bms. Also pain in the pancreatic area. It then darkened up when I took some stomach herb pain killers. The paing lessened too. I just did my second flush and well had some different results. Still got some aches not quite as bad as before but too early to tell, as well too early to tell for the BMs but so far still darkish. Also noticed some green soft balls covered in faecal matter this time in BMs after flush. Is this the stones that people talk about? If it is then it looked more like olive oil with some of the moisture extracted.