The first part of a hypothetical main Dalek origin timeline based on the following three assumptions:
1.The main divergence point is whether or not Davros survived Genesis of the Daleks posited by The Discontinuity Guide.
2.That every non I,Davros/Genesis of the Daleks origin are artificial created by the Daleks as a .T.T&L.G.T.W. tactic or inuniverse fiction.
3.That Destination Skaro is the fast return switch sending him to the Dalek Dome's crappy, "Genesis Zone" which is based on damaged records and used androids so wasn't affected by what happened. It did feel like a tacky, "relive/be part of the Dalek's origin!" tourist thing.
Timeline
240.B.C.= Age of Unreason: Start of the Kaled-Thal War. A Thal spy is captured in the military research and the broadcast of their recorded confession acts as the spark that starts the conflict. The first day's mutual neutronic bombardment destroyed the vast majority of both sides's non-domed cities and petrified vast tracts of forest. Within the year both sides had exhausted their neutronic and atomic arsenals thus shifted to a combination of: conventional, chemical, and biological warfare. It soon became obvious that the conflict would be one of slow attrition. (Approximation and speculation).
140.A.D.= Both sides adopt the policy of formally banishing those too damaged and malformed by the war's fallout, (ie: Mutos) to the wastelands. (.T.V. Genesis if the Daleks).
677.B.C.= Kaled Yarvelling dared her ten year old half brother Davros to investigate the Handmine field, he is subsequently rescued by the 12th Doctor using the 11th Doctor's sonic screwdriver which Davros retains. The incident haunts Davros's thoughts for a while. (.T.V. The Witch's Familiar, .N.S.A. Origin Stories: The Last Dals).
683.A.D.= The events of both .B.F. I, Davros: Innocence and two weeks later .N.S.A. Origins Stories: The Last of the Dals).
696.A.D.= The events of .B.F. I,Davros: Purity.
708.A.D.= Scientific Corp member Sharn presents, "The Dalek Solution" which revealed that the Kaled's radiation induced mutations would genetically stabilise in 200years as the later known mutant she calls a Dalek, (as an anagram) that thrives on Skaro's irradiated atmosphere and recommends that the Kaled race's only chance is to forcibly convert itself as quickly as possible into this inevitable new form. (.B.F. I,Davros: Corruption & Davros). Davros uses the Corp's resources to examine and analyse the Eleventh Doctor's sonic screwdriver he had in his possession discovering a defensive laser function he develops into a neutronic energy weapon powered by a dynamic generator. (.N.S.A. Origins Stories: The Last Dalek, .T.V. Closing Time).
759.A.D.= The events of .B.F. I,Davros: Guilt.
760.A.D.= The events of .T.V. Genesis of the Daleks. The Slats/Expansionist Daleks are temporarily entombed along with the Davros created, "production line", (ie: Automate cloning and casing manufacturing facilities).
760.A.D. to 799.A.D.= The Slats/Expansionist Daleks dig excavate the surface exit and expand their underground bunker complex to include: mines, research laboratories, an expanded, "production line", and later ship hangers. They develop antigravity and faster then light speed engines from a combination of the surviving Kaled Elite Scientific Corp's and Thal domed city ruin's records.
800.A.D.= The Slats/Expansionist Daleks send out reconnaissance scout ships throughout the galaxy. They are the first Daleks to leave Skaro.
906.A.D.= The Slats/Expansionist Daleks leave Skaro in saucer ships taking as much of their facilities with them leaving an empty bunker network and begin their attempts to establish an empire in the outer limits of Mutter's Spiral.
908.A.D.= The remaining Kaled, (and possibly Muto) population has naturally mutated into the Dalek form Sharn predicted retaining their original skin colour and, (now rather stunted) emotions. These are known as the: Bands/Exterminator Daleks. They start exploring and rebuilding the Kaled domed city ruins discovering information regarding Davros's Slats/Expansionist Dalek casing design but lacked the knowledge and resources to fully replicate them especially the independent energy supply so resorted to utilising static electricity instead.
920.A.D.= The Bands/Exterminator Daleks finished rebuilding the city with metal floors to generate unductive static electricity deciding to retain it's Kaled name, "Kalaann". They also discover the Slats/Expansionist Dalek's abandoned empty bunker network which they incorporate into the city's infrastructure.