Poison mastery and Master toxicist question

There's a mastery for poison that increase poison damage to non-poisoned enemies by 300%, The assendency Master toxicist gives the poison stacks to nearby enemies when they die during flask effect.

So my question is

If I kill a enemy with 20 poison stacks on them, will the 20 poison stacks be increased by 300% for EACH stacks on the nearby enemies since they aren't poisoned? or does it work at all? it should since they weren't poisoned but now they are because of toxicist.

How will the mastery be calculated here? will only 1 stack have the 300% increase? or will all stacks get 300% increase since they all got given at the same time to a non-poisoned enemy? or it simply won't work?

Only the strongest poison is transferred, and I do not think that it benefits from your damage modifiers again since those already applied when the poison was inflicted in the first place.

If you kill an enemy before the first poison you inflict wears off, there is a high chance that the poison that ends up being transferred to others is the one that benefits from the 300% increased damage.

Also, due to the way this poison spreading mechanic works, if another enemy dies with a copy of that poison, a third enemy that is already affected by a copy of that poison can still be affected by a copy of the copy. And if the original copy was based on a poison with 300% increased damage because it was inflicted on a non-poisoned enemy, both copied poisons will have the damage from that modifier.

thanks for the information, really confusing but I think I get it.