White/greens(yellows) are morning time leaves as Kratom is a cousin to coffe provideing mood lift and energy with big WD benefits. Yellow leaf is just white/green leaves dried in a different method. Where Red(Gold) is a night time are more painkilling leaves. Much more opiate like where Gold is simply a red leaf dried in a different manner. Some folks will recommend red for WDs but I also found a good green/white, like Manga Da, is best to get you moving in the morning where reds have a much more relaxing aspect. Kratom also benefits depression as it hits the gaba receptors along with the opiate receptors.

More research needs to be done to answer your tolerance question, but prior to finally breaking free from opiate addiction via kratom, when I relapsed it definitely felt like I hadn't taken a break at all. One time I slipped after 3 months and I still needed a dumb amount to even feel anything. Hope this helps!