> you could probably rule out (and mabye rule-in, determine) the redacted name, based on font-size, kerning etc in the document.
Depending on what you're redacting you can eliminate this variable.
For example when I want to redact a piece of sensitive text in a video often times I'll make the solid black bar longer than the text being hidden. This way you can't infer the length of it based on the length of the bar. Of course this only works when you can extend the bar in such a way where it won't hide non-sensitive info that's important to see. In practice it works well, for example for redacting browser history just make the bar the entire width of the browser URL bar and for API keys or secrets often times the key exists as an env variable on its own line so extending the black bar is no problem.
Depending on what you're redacting you can eliminate this variable.
For example when I want to redact a piece of sensitive text in a video often times I'll make the solid black bar longer than the text being hidden. This way you can't infer the length of it based on the length of the bar. Of course this only works when you can extend the bar in such a way where it won't hide non-sensitive info that's important to see. In practice it works well, for example for redacting browser history just make the bar the entire width of the browser URL bar and for API keys or secrets often times the key exists as an env variable on its own line so extending the black bar is no problem.