Very minor thing. Some webarchives (like for http://www.strangebeautiful.net/?page_id=52) will display like the original page, ie with a margin, in Safari but flush with the left window border in EF, making them less readable.
As far as I can tell, this page displays properly in EagleFiler. Please e-mail me your Web archive file so that I can try to reproduce the problem.
You’re right. I was confused by window sizes and did not take into account that the site’s stylesheet might be this crappy.