One thing I definitely notice- when I have a heavier longer kava drinking day, like 50 grams root, plus maybe 5 to 10 grams instant- the next day, much less whoops my arse.
So I think, not actually in direct relation to reverse tolerance, either as a newbie or a returner....but tolerance in general. For me it seems to quickly stabilise and regulate itself at a certain, fairly constant level.
So many other natural and synthetic compounds do not exhibit this same characteristic as Kava here.