TalkChess.com

Hi,
I was wondering how much Elo have your engines gained approximately with the insertions of singular extensions (and multicut).
I'm trying to implement it in my engine, but I get a small gain (~20 Elo), so I'm wondering if I have a bug somewhere, because I was expecting more from it.

SE is a famous "strong engine" heuristic, how much it gains for you is highly dependant on how sharp your search and eval already are.
In general when working on a new feature there is no value an heuristic "should" gain, if it's implemented properly it gains what it should gain, if it's bugged it will probably not gain 20 Elo.
Since you are in the active process of developing an engine and seem to have a fair share of doubts i suggest you join the SF discord server, it's way more active and populated with more competent devs than talkchess is.