3) Modify the domain it acts on if you're using a different pod
= = = = = ADDITIONAL NOTES = = = = =
diaspora is the most refined, with a lot of extra features like multicolumn comments, autoexpand all posts, font size customization, and other UI enhancements
Tumblr is also solid; it keeps the standard width of Tumblr posts and is responsive to width (2 or 3 columns)
Mastodon is maybe 95% good, depending on how you prefer to use Mastodon.
Hubzilla is maybe 80% good. Because of the right sidebar, this is limited to two columns by default.
Friendica is maybe 60% good. There's some sort of vertical scrolling bug when the left sidebar is too tall. If the left sidebar is short enough to fit on screen, all is good. But if the left sidebar is too tall, then scrolling gets stuck when you're too near the bottom of the content.
YouMe is maybe 40% good. It works, but it also affects single post view. And YouMe itself is really buggy right now (it only just launched). But the good news is that my userstyle can be used to produce single column (it's normally 2 column, which not everybody likes).
MeWe is maybe 50% good. As with Hubzilla, the right sidebar limits available space. So, it only provides 2 columns by default. And due to the complexity of MeWe, it only applies to the home and Groups pages - so, only single column view if you go to a single group. But as far as I've noticed, it's not buggy.
Of these platforms, the only ones I use significantly are diaspora, Tumblr, and Mastodon. Those will be the best supported, naturally.