Thanks Dimitry for clarifications.

I did not know about $this syntax. This is indeed explained here.

This will call the child/extended method and the superclass method, I want to bypass that and call base/super method directly.

Can you provide a link to the documentation (or an example) that show how to use the classes you mention in Ensemble ? 

EDIT : is this what you are talking about when referencing "pool sizes" : 
https://docs.intersystems.com/latest/csp/docbook/DocBook.UI.Page.cls?KEY=ECONFIG_PoolSize