Eric, if you like the feel of flats but want a brighter sound, have you tried half rounds? I experimented with about 6 different sets of strings (flat, round, nickel, steel) last year. I didn't include the half rounds that I used years ago and really liked (duh!). I got some a few months ago for my Epics and really like them. For me the string search seems to be over, for now anyway. I don't know how many companies make them but the ones I have are by D'Addario.
Rich