I just have gotten the issue resolved (at least for the next three years). Steve Smilanick, who patented S&S coupling, was very prompt in responding to me. For reference of anyone else who may be interested in a S&S retrofit, here's what he said regarding the ovalized tubes.
Originally Posted by Steve Smilanick
Thank you for your inquiry regarding S and S Couplings. Bilenky has done numerous retrofits on tube that are other than round and I haven't heard of a single complaint. Bilenky routinely does work that others say is impossible. He has a great reputation and I can't imagine him doing anything that would tarnish his standing in the cycling community.