I would like to cook as many meth as possible in Rats - Day 1. I'm wondering what are the possible numbers of meth ingredients / chemicals (or how are their numbers randomized), so I and my team will know when to stop looking for more ingredients. If it matters, I usually play on the Overkill difficulty.
Also, do the ingredients always spawn in sets of three? e.g. If my team has a total of two different ingredients, then is it guaranteed that the third ingredient is still out there?