I'll just throw this out here...
This article from 1948 by Margaret Titcomb
http://www.jps.auckland.ac.nz/document/?wid=2481
has some historical descriptions of the effects that traditional kava drinkers experienced, and there are a couple pertinent passages that are suggestive.
On the one hand, there are a couple places where it is emphasized that there are no after effects felt by kava drinkers the following day, which would suggest purely noble kava:
"The effect of 'awa, then, varied greatly according to the amount taken and frequency. Still leaving it in relative terms, a moderate amount was beneficial, excessive use gradually impaired strength and hastened the debilities of age. The effect on the mind was not harmful, except to dull it when under the influence of an excessive amount, and after moderate drinking no after effects remained."
"In modern times, 1903, Emerson made his own observations of the effect of awa (19, p. 135).
“The Hawaiian is muscular and given at times to prolonged exertion and exposure which induces excessive weariness, and awa by relaxing the muscles and inducing sleep gives him relief. On stopping overnight a few weeks ago at a native house, preparatory to climbing out of Pelekunu valley and over the summit of Kilohana, Molokai's highest mountain, I was surprised in the evening to find my host drinking awa. In the morning we were to start on our wearisome and difficult tramp and here he was making himself stupid with awa. I felt anxious for the result, but I need not have been so, for in the morning he told me that he had had a fine night's rest and felt well prepared for the day's work. The climb proved the truth of his words, for he went far that day, climbing the face of a steep mountain wall over five thousand feet high, where hands as well as feet came into constant requisition, and he carried a heavy burden strapped to his back all the way . . . On the following evening he again took awa, remarking that it would take away the soreness of his muscles and give him a good night's rest. The next morning he was up early, bustling about as actively as usual . . . He told me that the first cup did not make him sufficiently drunk and that in order to get the full benefit he had to take a second, and then when the flame of the lamp seemed to be double, as if two lamps were burning he fell off into a profound sleep, so profound that he did not turn over till morning.” "
But, on the other hand, there is also this, quoting someone named Kamakua in 1869:
“People in the old days liked awa as a means of reducing weight. When a man saw himself growing too fat and subject to illnesses, the best thing was to drink copiously like the gods and like those possessed of a spirit until the skin scaled. Let him look for the potent awa and buy a large quantity, then begin to drink, and eat nothing between meals. Fish and poi were to be eaten only when the cup of awa was drunk. One must not go out in the sun and rain lest the feet crack if wet in water or mud. [Note: Because the skin became thin and dry—Pukui.] The first cup was enough to make one drunk for two days. The day after a man had become intoxicated drinking awa, he would be intoxicated again when he drank awa, when he bathed in sea water or when he ate. This effect lasted two or three days. Then if he took it again his head would grow heavy and his eyes pucker up, and with the third cup the heavy feeling would go down to the chest, and when the cups of awa were continued his skin would begin to scale and he would begin to lose weight. The scales would peel off, then more awa was taken as medicine, combined with a cathartic to act as a double net to clean out the body, and after three, four, or five cups of awa the body became spare.
“Then a pig was sought as an offering for the breaking up of the awa bowl, a feast made, the awa bowl broken, and the drinking of awa was ended and sea water was drunk. The effects of the awa would then cease, the body would be thin, the illness would be gone, and the body recover its fitness.”
So, could this actually be a description of historical use of some kind of medicinal/tudei cultivar in Hawaii? Or is it simply over-dramatic and exaggerated language by the Victorian author? Is it really saying that a single cup of kava could make someone intoxicated for two days, or does the reference to buying a "large quantity" just mean that the dieter stays intoxicated because he keeps drinking lots of kava for a period of time?
