@feditips Thanks! I finally did a test. Typing this into @Ivory says I have 257 characters left. If I paste this same text into the Mastodon app (macOS) it says I have 244. So the apps do change it a bit - I swear I've seen bigger differences.
Like it says in the beginning, you don't need to read all of it - I skimmed the sections about starting an instance & tools. I would vote for @Ivory be included in the next edition 😁
I'm still confused how the character limit gets set for replies. Does it follow the original post? or is is set by the instance you are on, or the app/platform? Maybe it's all in my head.