Four years ago I was told that due to my bad back I would never be able to ride a DF bike again so I switched to recumbents. I have owned 3 and love two of them. However I like to tour and shipping a recumbent across country is very expensive. My LBS said they could make a LBS work for me and they did by installing a stem extension and installing anextended seat post with suspension. I sit straighter and no lower back pain. There was a bit of experimenting with heights of both of these components but I now have the sweetest DF ride I've ever had. It's fast, it tours well and it ships cross country for $50 versus the $300 for the recumbent.
Experimenting and trying out different bicycles and geometries are the key