Are you talking a 7-8 IGH with a coaster, or are you running a rear centerpull as well? I don't know if my personal experience will help or not, but I had a centurion a little while ago that I put bar end shifters at the ends of some chopped drops converted into bullhorns, I was able to use some non aero levers I had laying around with a pair of mafac racers, mounting the levers on the bottom at the tips of the horns, it was actually quite nice. You want to run interrupters so you have levers available in the flats I take it?