scale at twice the dpi whenever possible. Do not reduce the quality. Generaly speaking, even for close ups, I very rarely go over 1024 in the largest dimension. In a situation such as your example, I might get iffy and run around 1536 or so.

thou and I, my friend, can, in the most flunkey world, make, each of us, one non-flunkey, one hero, if we like: that will be two heroes to begin with. (Carlyle)