There is no firm answer on this. Here's how it works:
Plastic is made from PVC (poly vinyl chloride)
When PVC is heated to 350+ the vinyl and chloride split. In the absence of any stabilizer the chloride will reattach itself to the vinyl (this is what causes yellowing). In the presence of stabilizers the chloride will attach itself to the stabilizer - a stabilizer can only be attached to once.
What determines the amount of chlorides produced is the temp your plastic is heated to, and how long it is kept there.
The better you manage your temps, the less stabilizer you need.
Why not just add a bunch of stabilizer and not worry about it? Excess stabilizer can cause oily smelly baits. So you only want to use what is needed.
This is why I really encourage only cooking what you are going to use in the present. If you are going to use 2 oz. of plastic per round, there's no reason to heat 16 oz. of plastic and have to warm it up 8 times to use it all - you start getting into plastic management.
There are way to many variables to say add x drops after x reheats. With my setup, I normally will cook a cup 3 times before adding 4-6 drops of stabilizer or fresh plastic and a couple drops of stabilizer. In an ideal world I would cook X cups, use all of it and make up a new batch and put my scrap in it - no stabilizer needed.
Hope this helps a little.
Jason
