But then again, seeing how much of SFAM was written with Derek, SDOIT is probably the first proper sample of unique JR's sound and ideas transferred onto DT.
Despite his participation in the SFAM "demo", I don't believe DS contributed much to the final album at all. SFAM is in fact arguably the most undiluted "JR" that JR has ever been allowed to be in DT, aside from maybe SDOIT. JR's stamp is undeniably all over SFAM from start to finish, and that fresh sound is a lot of what makes that album so amazing imo, not the tiny dribs and drabs drafted while DS happened to be in the band.
The demo was mostly 20 minutes of rough noodling, and how much of that made it in? Some main keyboard parts of Overture 1928 are in there, the outro run from TDOE that is just doubling JP, which I would assume JP wrote anyway based on the pattern and performance, and sections of One Last Time that are based around a signature JP melody, where the keyboard is just playing the most rudimentary of accompaniment on a hammond, which got replaced with something better by JR. I was skimming, so maybe there's something else in there too, but no developed ideas or signature DS parts that I spotted.
So only a small portion of the final album was even written while DS was in the band, and I'd only credit him with himself writing an even smaller portion of that. I'd only give him credit for Overture 1928. Had he not been involved, it would hardly have changed a thing imo. The greatness of SFAM comes largely from the fresh writing dynamic of JP/JR.