Using a content warning is best in general, since blocking specific tags is a task the viewers must do to stop seeing the content, rather than a task they must do to begin seeing it. It also allows one to describe the content more accurately before the viewer decides to open the content warning.
However, tags can be muted as you say, and since the content in question isn't questionable in the slightest, you're fine to continue as you are unless someone specifically asks that Hiveswap spoilers be behind a content warning.
A Homestuck Instance. Just all of the Homestuck. All of It.