Glad it worked out technically. Results may take some time. I'd really focus on sending high-value content for your audience and let nature start to take its course.
You might consider leveraging the Customer Engagement Engine, which is all about establishing a cadence, and makes it super simple to add content over time without having to worry about who already got what, where people are in the flow, etc.
Furthermore, the new Email Program with much easier A/B testing capabilties is something to investigate.
Mark's suggestion is somethign to work toward. The system part of that isn't that difficult. It's creating the content versions that can take the majority of time. Of course, sometimes that can also be simple, such as creating different versions of the subject line, or swapping a different case study depending on industry, etc., which doesn't take much time.