Leave until last!! I told my DS to ignore them and come back only if time, which I knew there wouldn't be. To me they seemed so much effort for, presumably, just one point. I hope and pray the answers aren't weighted. I confess we didn't do very many. They vary so much and we didn't agree with some of the answers. Although they are designed to test logic they're not all strictly logical themselves, we found. In fact they made my blood boil at times.
Sorry, I haven't got any further advice except use a line for these.