While the typology of the eight day was developing in orthodox gnosis [Roman Christianity], it was having a consideable success in... heretical gnosis.
The Gnostics, who were decided enemies of Judaism, were carried away by this theme.
Epistle of Barnabas, XV, 8-9
The present sabbaths are not acceptable to me, but that which I have made, in which I will give rest to all things and make the beginning of an eighth day, that is the beginning of another world. Wherefore we also celebrate with gladness the eighth day.
Primitive Christianity in Crisis, Alan Knight, page 65
I think the only possible conclusion is that Sunday and Eight Day worship did have significant theoligical meaning when it was first introduced in the early church. Though less radical in condemning material existence, Hellenistic Christian Eight Day theology takes the same general form as in the mainstream Gnostic and Pagan Hellenistic tradition. It rejects the material world and looks forward exclusively to a non-material spirituality of the heavens.... Clement expressed the same idea by associating coming out of sin with rising above the seven spheres of the material world and passing beyond the enumeration of time into seven periods, finding true rest in the Eight Day rather than in creation rest. This is classic Gnostic theology.
FRegards, KU04
But thanks for trying.