post listing layout on recent posts and category/archive pages (free Decree)

Hi, I have 2 questions: 1. I'm using a static page for home, and a different page for recent posts. On the recent posts page, 4 post excerpts are shown per row; on category pages, just 1. How do I control that? Not sure if I will prefer 2 or 3 posts per row, will need to see that, but would like the same number of post columns on all archive-type pages (including recent posts). 2. How do I add some space between the image thumbnails so they don't touch each other when displayed side by side? Thank you! LM