Alt S.S. kind of sucks through, Dragon & it's wording isn't much different from Southern Magician which doesn't allow you to do such so it can provoke arguments.
As an alternate suggestion I'd go with Divine Bard & Domains, you can land hundreds of Arcane->Divine Spells that way. For the Domains you can either keep retraining a level of competitive or purchase & resell Domain Staffs.
And if you want to go for broke, a
Hexer theoretically adds all Sorcerer/Wizard Spells to the list of possible Spells an Archivist can learn. It's unupdated 3.0 through.