The Retch - Scaling

Hello

From a previous thread from 2017, named Game mechanics questions, Mark_GGG answered the following question

"When wearing the Retch, if you are leeching from many enemies simultaneously, such that your maximum leech rate is reached, so that the leech from many of those enemies are not actually giving you any further recovery, do those enemies still take chaos damage from the Retch's modifier? "

With

"Yes. Your total recovery per second from Leech is capped, but the damage to enemies has no cap."

In that regard I attempted to make a build using the Retch, to scale my leech instance as high as possible -
Via 2 * the Highwayman for Double total leech per second
Vaal pact double leech per second
So the 2% normal hit would assumably be 16%, and then scaling it with the total recovery per second from notes such as Martial Experience, small node at Gladiators perserverance, Vitality void, Lust for carnage and Hematophagy.
This should resulting in me leeching on a single target, about a fourth of my damage. I would from this assume that, if I stopped hitting a target, I would see some sort of DoT affect targets I attacked.
However this DoT seems to tickle at best, so I'd just like to know how the Retch is actually supposed to scale. Or if there is a bug with how it's currently working

Thanks in advance.