I have not read this. Bentonite is a clearing agent. Some people do it during fermentation some do it afterwards.
From what I read, *IF* you plan on using it, it should always be during fermentation because after fermentation requires much more bentonite. The reason being is that during fermentation, the CO2 gas helps circulate the bentonite by attaching to the CO2 bubbles and as the bubbles rise and reach the top. They pop which then allows the bentonite to move in the must. Which then allows other floating particles to attach to the bentonite helping the clearing process.
Bentonite strips the wine (which is what clearing is), if you have to use more. You stripe more of the wine which is a negative in most cases.
While some people do not like to use clearing agents, bentonite is probably one I would use before chitosan. Just for the fact that it helps stabilize the wine and of course removes much of the haze causing particles which can be difficult to remove without clearing agents sometimes I've heard.
Most of the time I believe 15 grams is considered enough during fermentation for six gallon kits. Post fermentation can require 5x as much! (I suppose you can use the same amount after fermentation, but you will be stirring the must early and very often to get the same effects) It is interesting that this kit comes with 2x the bentonite. I suppose it has something to do with the contents of the juice and skins packs requiring heavier clearing requirements in the early processes.
As I said though. I'm with you in that I would use the bentonite before the chitosan.
You are correct. I meant to type "during" fermentation, rather than during clearing.