Tricky question this. I really dislike UD aisle seats so I'd go for windows in 62 and 64 and therefore Travel separately. However, for people who don't mind those aisle seats I'd go for 63 pairs if one of you is agile. That way no one has to climb or be climbed over and you have the benefits of not facing a stranger during the briefing. Plus it is nice to occasionally chat to your companion.