The New Theme -- following up.
I've gone through the rest of the items that I care about, and adjusted them.
I've also only tested this on Chrome. Why? Because I made it for me, not really for the public. I'm throwing it out there for the world in the hopes that somebody else might find it useful, too. And because a few people asked me about it.
Right now I'm satisfied with how this looks in chrome. As the site continues to evolve I'll probably make more changes to it as I see fit.
For easy installation and better distribution I've posted the script on userstyles.org. That way I won't need to provide further installation instructions. You can follow the link and use the "Install it" button.
Without this I was able to see just one post on a page. Now I can see about 3 posts on a page. There is more information, and it doesn't limit me to 1250 pixels when I go full screen. Full screen on my big monitor shows about 5 posts per page. That's enough to satisfy my craving for seeing nearby posts when composing a reply. And that's all I really wanted.