Will there be a Mac compatibility mode for the new v1.6.3 (or later) version of SDV? I see the v1.5.6 version of this installer but it would be great to have a v 1.6.3 version too.

GOG kinda shot itself in the foot here as GOG Galaxy is not supported below 10.15 and most 32bit OSes are FAR below this requirement, but it's the only way to access extra version branches and older versions of the game. This needs to change. Offline installer version history and extra branches should be accessible on the web interface specifically for situations like this.