I had gathered information from a RLS forum I was on before I knew I had PN. Many posters there use Kratom. The consensus was:

"Red Borneo powdered leaf variety seems to have the highest pain-killing and sedating properties. In general the red vein varieties are best for evening, green and white are generally better for daytime."

also, which might be of interest;
Kratom works within a half an hour if dissolved in orange juice first first, and let it sit for twenty minutes. Kratom is not water soluble, but does dissolve in acid: hence the use of orange juice.

I must reiterate that this information is not from personal experience but I do plan on using it if and when I order this.