I think you're doing pretty good. Keep at it. You might want to try looking for Galaxy 17. It's fairly close to your true south plus it has quite a bit of activity on a given evening. Whatever satellite you choose to look for next, I think you'll find this post from Iceberg helpful.
http://www.satelliteguys.us/free-air-fta-discussion/85225-i-need-strong-transponder-aim-my-dish.html
Is this list still valid since some of those have moved to different locations?
According to Lyngsat, there does not seem to be much to aim for on 91 W that isn't a feed.
Will an FTA box hit a quality reading on a HughesNet transponder? I've not been sucessful in registering any that are listed on Lyngsat on 91.