I mostly just open all via "open unread" items and close with ctrl+w (I don't really use the mouse that much) I prefer my tabs at the top, really, never been a fan of sidebars As I always open all unread in the forums I'm interested in, just to have them marked as read, I don't really care about scanning that much, and it's usually not much more than a maximum of 5-10 unread items pr. subforum... I don't mind 30-40 tabs being open. However, the bookmarks bit is good, I just suck at using bookmarks - I used to be good, having hundreds of bookmarks neatly categorized, but the later years I usually can't be arsed - I visit few sites, and if I can't remember the name, I just google for it, or search through history. Should be better at bookmarking things I wanna keep, though.
Or you can remove the repeat value all together. The background image will repeat to both directions by default.