I created three different versions of one Mac icon in Sketch ranging from least detailed (small version) for 16x16 to most detailed (large version) at 512x512. The plugin I use in Sketch exports an artboard into an icns file that include all the necessary resolutions for implementation. This is helpful because implementation of Mac icons only allow for one file. However, I want to be able to use the small version of the design for 16x16/@2x, 32x32/@2x; the medium version for 128x128/@2x; and the large version for 512x512/@2x. But I'm finding it hard/have no resources for combining all of those versions into one icns file.
I find it pretty disheartening since the HIG recommends designing less detailed versions of the same design for smaller resolutions from what I understand.
Does anyone have any advice, resources or workaround? Thanks!