Adjust instance composite

Is it possible to adjust the composite of a instance? I have following scenario: Three masters, Thin, Regular, Black. The ogonek connects at the full width of the stroke in thin and regular, in the black however the connection in finer. Now I would like to have the medium similar connected as the regular, using the full stroke width. Anyone knows how to do this? See the image attached, the detail in question is marked with the red circle.

You need to use brace layers to insert an intermediate version of the ogonek.

Ah, I tried this but it didn’t work because I have done it wrong. Now it works. Thanks!